diff --git a/apps/ac_ac/Customizer.html b/apps/ac_ac/Customizer.html
index 59c08f2cd..5c60c0aa4 100644
--- a/apps/ac_ac/Customizer.html
+++ b/apps/ac_ac/Customizer.html
@@ -26,13 +26,10 @@
     default-src 'self' 'unsafe-inline' 'unsafe-eval' file: https:;
   ">
 
-  <script src="jquery-3.6.0.min.js"></script>
-  <!--script src="https://code.jquery.com/jquery-3.6.0.min.js"></script-->
+  <script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
 
-  <link rel="stylesheet" href=""https://cdnjs.cloudflare.com/ajax/libs/spectre.css/0.4.5/spectre.min.css">
-  <!--link rel="stylesheet" href="../../css/spectre.min.css"-->
-  <script src="customize.js"></script>
-  <!--script src="../../core/lib/customize.js"></script-->
+  <link rel="stylesheet" href="../../css/spectre.min.css">
+  <script src="../../core/lib/customize.js"></script>
 
   <style>
     body { background:white; color:black }
@@ -125,17 +122,220 @@
 
 
   <script>
+  $(function () {
+    let ClockSize, ClockSizeURL
+    let ClockFace, ClockFaceDots, ClockFaceURL
+    let ClockHands, SecondHand, ClockHandsURL, FillColor
+    let ComplicationTL, ComplicationTLURL
+    let ComplicationT, ComplicationTURL
+    let ComplicationTR, ComplicationTRURL
+    let ComplicationL, ComplicationLURL
+    let ComplicationR, ComplicationRURL
+    let ComplicationBL, ComplicationBLURL
+    let ComplicationB, ComplicationBURL
+    let ComplicationBR, ComplicationBRURL
+    let Foreground, Background
 
+  /**** retrieveInputs ****/
 
-/*
-    let AppSource = ''
+    function retrieveInputs () {
+      ClockSize    = $('input[name="clock-size"]:checked').val()
+      ClockSizeURL = ($('#clock-size-custom-url').val() || '').trim()
 
-    sendCustomizedApp({
-      storage:[
-        {name:'ac-ac.app.js', url:'app.js', content:app},
-      ]
-    });
-*/
+      ClockFace     = $('input[name="clock-face"]:checked').val()
+      ClockFaceDots = $('input[name="clock-face-dots"]:checked').val()
+      ClockFaceURL  = ($('#clock-face-custom-url').val() || '').trim()
+
+      ClockHands    = $('input[name="clock-hands"]:checked').val()
+      FillColor     = $('input[name="fill-color"]:checked').val()
+      SecondHand    = $('input[name="second-hand"]:checked').val()
+      ClockHandsURL = ($('#clock-hands-custom-url').val() || '').trim()
+
+      ComplicationTL    = $('#complication-tl').val()
+      ComplicationTLURL = ($('#complication-tl-custom-url').val() || '').trim()
+
+      ComplicationT    = $('#complication-t').val()
+      ComplicationTURL = ($('#complication-t-custom-url').val() || '').trim()
+
+      ComplicationTR    = $('#complication-tr').val()
+      ComplicationTRURL = ($('#complication-tr-custom-url').val() || '').trim()
+
+      ComplicationL    = $('#complication-l').val()
+      ComplicationLURL = ($('#complication-l-custom-url').val() || '').trim()
+
+      ComplicationR    = $('#complication-r').val()
+      ComplicationRURL = ($('#complication-r-custom-url').val() || '').trim()
+
+      ComplicationBL    = $('#complication-bl').val()
+      ComplicationBLURL = ($('#complication-bl-custom-url').val() || '').trim()
+
+      ComplicationB    = $('#complication-b').val()
+      ComplicationBURL = ($('#complication-b-custom-url').val() || '').trim()
+
+      ComplicationBR    = $('#complication-br').val()
+      ComplicationBRURL = ($('#complication-br-custom-url').val() || '').trim()
+
+      Foreground = $('input[name="foreground"]:checked').val()
+      Background = $('input[name="background"]:checked').val()
+    }
+    retrieveInputs()
+
+  /**** validateInputs ****/
+
+    function validateInputs () {
+      function withError (Message) {
+        showMessage(Message)
+        $('#UploadButton').attr('disabled',true)
+      }
+
+      switch (true) {
+        case (ClockSize === 'custom') && (ClockSizeURL === ''):
+          return withError('please enter the URL of your custom "Clock Size Calculator"')
+
+        case (ClockFace === 'custom') && (ClockFaceURL === ''):
+          return withError('please enter the URL of your custom clock face')
+
+        case (ClockHands === 'custom') && (ClockHandsURL === ''):
+          return withError('please enter the URL of your custom clock hands')
+
+        case (ComplicationTL === 'custom') && (ComplicationTLURL === ''):
+          return withError('please enter the URL of your custom complication in the top-left corner')
+        case (ComplicationT === 'custom') && (ComplicationTURL === ''):
+          return withError('please enter the URL of your custom complication at the top edge')
+        case (ComplicationTR === 'custom') && (ComplicationTRURL === ''):
+          return withError('please enter the URL of your custom complication in the top-right corner')
+        case (ComplicationL === 'custom') && (ComplicationLURL === ''):
+          return withError('please enter the URL of your custom complication at the left edge')
+        case (ComplicationR === 'custom') && (ComplicationRURL === ''):
+          return withError('please enter the URL of your custom complication at the right edge')
+        case (ComplicationBL === 'custom') && (ComplicationBLURL === ''):
+          return withError('please enter the URL of your custom complication in the bottom-left corner')
+        case (ComplicationB === 'custom') && (ComplicationBURL === ''):
+          return withError('please enter the URL of your custom complication at the bottom edge')
+        case (ComplicationBR === 'custom') && (ComplicationBRURL === ''):
+          return withError('please enter the URL of your custom complication in the bottom-right corner')
+      }
+
+      hideMessage()
+      $('#UploadButton').removeAttr('disabled')
+    }
+
+  /**** hide/showMesssage ****/
+
+    function hideMessage () { $('#MessageView').hide() }
+
+    function showMessage (Message) {
+      $('#MessageView').text(Message).show()
+    }
+
+  /**** createAndUploadApp ****/
+
+    function createAndUploadApp () {
+      function chosenClockSize () {
+        switch (ClockSize) {
+          case 'simple': return "require('https://raw.githubusercontent.com/rozek/banglejs-2-simple-clock-size/main/ClockSize.js')"
+          case 'smart':  return "require('https://raw.githubusercontent.com/rozek/banglejs-2-smart-clock-size/main/ClockSize.js')"
+          case 'custom': return 'require(' + ClockSizeURL + ')'
+        }
+      }
+
+      function chosenClockFace () {
+        switch (ClockFace) {
+          case 'none':        return undefined
+          case 'four-fold':   return "require('https://raw.githubusercontent.com/rozek/banglejs-2-four-fold-clock-face/main/ClockFace.js')"
+          case 'twelve-fold': return "require('https://raw.githubusercontent.com/rozek/banglejs-2-twelve-fold-clock-face/main/ClockFace.js')"
+          case 'rainbow':     return "require('https://raw.githubusercontent.com/rozek/banglejs-2-rainbow-clock-face/main/ClockFace.js')"
+          case 'custom':      return 'require(' + ClockFaceURL + ')'
+        }
+      }
+
+      function chosenClockHands () {
+        switch (ClockHands) {
+          case 'simple':  return "require('https://raw.githubusercontent.com/rozek/banglejs-2-simpled-clock-hands/main/ClockHands.js')"
+          case 'rounded': return "require('https://raw.githubusercontent.com/rozek/banglejs-2-rounded-clock-hands/main/ClockHands.js')"
+          case 'hollow':  return "require('https://raw.githubusercontent.com/rozek/banglejs-2-hollow-clock-hands/main/ClockHands.js')"
+          case 'custom':  return 'require(' + ClockHandsURL + ')'
+        }
+      }
+
+      function chosenComplication (Complication, customURL) {
+        switch (Complication) {
+          case 'none':          return undefined
+          case 'date':          return "require('https://raw.githubusercontent.com/rozek/banglejs-2-date-complication/main/Complication.js')"
+          case 'weekday':       return "require('https://raw.githubusercontent.com/rozek/banglejs-2-weekday-complication/main/Complication.js')"
+          case 'calendar-week': return "require('https://raw.githubusercontent.com/rozek/banglejs-2-calendar-week-complication/main/Complication.js')"
+          case 'moon-phase':    return "require('https://raw.githubusercontent.com/rozek/banglejs-2-moon-phase-complication/main/Complication.js')"
+          case 'custom':        return 'require(' + customURL + ')'
+        }
+      }
+      function chosenComplicationAt (Position) {
+        switch (Position) {
+          case 'tl': return chosenComplication(ComplicationTL, ComplicationTLURL)
+          case 't':  return chosenComplication(ComplicationT,  ComplicationTURL)
+          case 'tr': return chosenComplication(ComplicationTR, ComplicationTRURL)
+          case 'l':  return chosenComplication(ComplicationL,  ComplicationLURL)
+          case 'r':  return chosenComplication(ComplicationR,  ComplicationRURL)
+          case 'bl': return chosenComplication(ComplicationBL, ComplicationBLURL)
+          case 'b':  return chosenComplication(ComplicationB,  ComplicationBURL)
+          case 'br': return chosenComplication(ComplicationBR, ComplicationBRURL)
+        }
+      }
+
+      function chosenColor (ColorChoice) {
+        return (ColorChoice === 'none' ? undefined : ColorChoice)
+      }
+
+      function chosenForeground () { return chosenColor(Foreground) }
+      function chosenBackground () { return chosenColor(Background) }
+      function chosenSecondHand () { return chosenColor(SecondHand) }
+      function chosenFillColor ()  { return chosenColor(FillColor) }
+
+      function chosenDots () { return (ClockFaceDots === 'with-dots') }
+
+      let AppSource = `
+let Clockwork = require('https://raw.githubusercontent.com/rozek/banglejs-2-simple-clockwork/main/Clockwork.js');
+
+Clockwork.windUp({
+  size:      ${chosenClockSize()},
+  background:null,
+  face:      ${chosenClockFace()},
+  hands:     ${chosenClockHands()},
+  complications:{
+    tl:${chosenComplicationAt('tl')},
+    t: ${chosenComplicationAt('t')},
+    tr:${chosenComplicationAt('tr')},
+    l: ${chosenComplicationAt('l')},
+    r: ${chosenComplicationAt('r')},
+    bl:${chosenComplicationAt('bl')},
+    b: ${chosenComplicationAt('b')},
+    br:${chosenComplicationAt('br')},
+  }
+},{
+  Foreground:${chosenForeground()},
+  Background:${chosenBackground()},
+  Seconds:   ${chosenSecondHand()},
+  withDots:  ${chosenDots()},
+  FillColor: ${chosenFillColor()}
+});
+`
+      sendCustomizedApp({
+        storage:[
+          {name:'ac-ac.app.js', url:'app.js', content:AppSource},
+        ]
+      })
+    }
+
+  /**** register event handlers ****/
+
+    function retrieveAndValidateInputs () {
+      retrieveInputs ()
+      validateInputs ()
+    }
+
+    $('input[type="radio"]').on('change',retrieveAndValidateInputs)
+    $('input[type="url"]').  on('change',retrieveAndValidateInputs)
+    $('select').             on('change',retrieveAndValidateInputs)
+  })
   </script>
 
 
@@ -167,7 +367,7 @@
 
      <td>
        <label class="Preview">
-         <input type="radio" name="clock-size" value="smart">
+         <input type="radio" name="clock-size" value="smart" checked>
          <img src="smartClockSize.png"/>
        </label><br>
        smart
@@ -186,7 +386,7 @@
   If you prefer a "custom" clock size calculator, please enter the URL
   of its JavaScript module below:
 </p><p>
-  custom URL: <input type="url" id="clock-size-custom-url" size="30">
+  custom URL: <input type="url" id="clock-size-custom-url" size="50">
 </p>
 
   <h3>Clock Face</h3>
@@ -198,7 +398,7 @@
    <tr>
      <td>
        <label class="Preview">
-         <input type="radio" name="clock-face" value="none">
+         <input type="radio" name="clock-face" value="none" checked>
          <img src="none.png"/>
        </label><br>
        none
@@ -244,13 +444,13 @@
   The "twelve-fold" and "rainbow"-colored faces may be drawn with or without
   dots marking the position of every minute. Which variant do you prefer?
 </p><p>
-  <input type="radio" name="clock-face-dots" value="without-dots"> without dots <br>
+  <input type="radio" name="clock-face-dots" value="without-dots" checked> without dots <br>
   <input type="radio" name="clock-face-dots" value="with-dots"> with dots
 </p><p>
   If you prefer a "custom" clock face, please enter the URL
   of its JavaScript module below:
 </p><p>
-  custom URL: <input type="url" id="clock-face-custom-url" size="30">
+  custom URL: <input type="url" id="clock-face-custom-url" size="50">
 </p>
 
   <h3>Clock Hands</h3>
@@ -270,7 +470,7 @@
 
      <td>
        <label class="Preview">
-         <input type="radio" name="clock-hands" value="rounded">
+         <input type="radio" name="clock-hands" value="rounded" checked>
          <img src="roundedClockHands.png"/>
        </label><br>
        rounded
@@ -296,6 +496,27 @@
 </p><p>
   Clock hands are drawn in the configured foreground and background colors
   (you may select them at the end of this form)
+</p><p>
+  Hollow clock hands may optionally be filled with a given color. If you have
+  chosen hollow hands, please specify the desired fill mode and color below:
+  <b>Hollow Hand Fill Color:</b>
+</p><p>
+  <label class="ColorPatch">
+    <input type="radio" name="fill-color" value="none" checked/>
+    <span>none</span>
+  </label>
+  <label class="ColorPatch">
+    <input type="radio" name="fill-color" value="Theme"/>
+    <span>themed</span>
+  </label>
+  <input type="radio" name="fill-color" value="#000000" class="ColorPatch" style="background:#000000"/>
+  <input type="radio" name="fill-color" value="#FF0000" class="ColorPatch" style="background:#FF0000"/>
+  <input type="radio" name="fill-color" value="#00FF00" class="ColorPatch" style="background:#00FF00"/>
+  <input type="radio" name="fill-color" value="#0000FF" class="ColorPatch" style="background:#0000FF"/>
+  <input type="radio" name="fill-color" value="#FFFF00" class="ColorPatch" style="background:#FFFF00"/>
+  <input type="radio" name="fill-color" value="#FF00FF" class="ColorPatch" style="background:#FF00FF"/>
+  <input type="radio" name="fill-color" value="#00FFFF" class="ColorPatch" style="background:#00FFFF"/>
+  <input type="radio" name="fill-color" value="#FFFFFF" class="ColorPatch" style="background:#FFFFFF"/>
 </p><p>
   Additionally, all clock hands may be drawn with or without second hands.
   If you want them to be drawn, please click on their desired color below
@@ -305,7 +526,7 @@
   <b>Second Hand Color:</b>
 </p><p>
   <label class="ColorPatch">
-    <input type="radio" name="second-hand" value="(null)"/>
+    <input type="radio" name="second-hand" value="none" checked/>
     <span>none</span>
   </label>
   <label class="ColorPatch">
@@ -324,7 +545,7 @@
   If you prefer "custom" clock hands, please enter the URL
   of their JavaScript module below:
 </p><p>
-  custom URL: <input type="url" id="clock-hands-custom-url" size="30">
+  custom URL: <input type="url" id="clock-hands-custom-url" size="50">
 </p>
 
   <h3>Complications</h3>
@@ -347,7 +568,7 @@
       <td> Complication:</td>
       <td>
         <select id="complication-tl">
-          <option value="none">         (none)</option>
+          <option value="none" selected>(none)</option>
           <option value="date">         date</option>
           <option value="weekday">      weekday</option>
           <option value="calendar-week">calendar week</option>
@@ -359,7 +580,7 @@
     <tr>
       <td></td>
       <td>custom URL:</td>
-      <td><input type="url" id="complication-tl-custom-url"></td>
+      <td><input type="url" id="complication-tl-custom-url" size="50"></td>
     </tr>
 
     <tr>
@@ -369,7 +590,7 @@
       <td> Complication:</td>
       <td>
         <select id="complication-t">
-          <option value="none">         (none)</option>
+          <option value="none" selected>(none)</option>
           <option value="date">         date</option>
           <option value="weekday">      weekday</option>
           <option value="calendar-week">calendar week</option>
@@ -381,7 +602,7 @@
     <tr>
       <td></td>
       <td>custom URL:</td>
-      <td><input type="url" id="complication-t-custom-url"></td>
+      <td><input type="url" id="complication-t-custom-url" size="50"></td>
     </tr>
 
     <tr>
@@ -391,7 +612,7 @@
       <td> Complication:</td>
       <td>
         <select id="complication-tr">
-          <option value="none">         (none)</option>
+          <option value="none" selected>(none)</option>
           <option value="date">         date</option>
           <option value="weekday">      weekday</option>
           <option value="calendar-week">calendar week</option>
@@ -403,7 +624,7 @@
     <tr>
       <td></td>
       <td>custom URL:</td>
-      <td><input type="url" id="complication-tr-custom-url"></td>
+      <td><input type="url" id="complication-tr-custom-url" size="50"></td>
     </tr>
 
     <tr>
@@ -413,7 +634,7 @@
       <td> Complication:</td>
       <td>
         <select id="complication-l">
-          <option value="none">         (none)</option>
+          <option value="none" selected>(none)</option>
           <option value="date">         date</option>
           <option value="weekday">      weekday</option>
           <option value="calendar-week">calendar week</option>
@@ -425,7 +646,7 @@
     <tr>
       <td></td>
       <td>custom URL:</td>
-      <td><input type="url" id="complication-l-custom-url"></td>
+      <td><input type="url" id="complication-l-custom-url" size="50"></td>
     </tr>
 
     <tr>
@@ -435,7 +656,7 @@
       <td> Complication:</td>
       <td>
         <select id="complication-r">
-          <option value="none">         (none)</option>
+          <option value="none" selected>(none)</option>
           <option value="date">         date</option>
           <option value="weekday">      weekday</option>
           <option value="calendar-week">calendar week</option>
@@ -447,7 +668,7 @@
     <tr>
       <td></td>
       <td>custom URL:</td>
-      <td><input type="url" id="complication-r-custom-url"></td>
+      <td><input type="url" id="complication-r-custom-url" size="50"></td>
     </tr>
 
     <tr>
@@ -457,7 +678,7 @@
       <td> Complication:</td>
       <td>
         <select id="complication-bl">
-          <option value="none">         (none)</option>
+          <option value="none" selected>(none)</option>
           <option value="date">         date</option>
           <option value="weekday">      weekday</option>
           <option value="calendar-week">calendar week</option>
@@ -469,7 +690,7 @@
     <tr>
       <td></td>
       <td>custom URL:</td>
-      <td><input type="url" id="complication-bl-custom-url"></td>
+      <td><input type="url" id="complication-bl-custom-url" size="50"></td>
     </tr>
 
     <tr>
@@ -479,7 +700,7 @@
       <td> Complication:</td>
       <td>
         <select id="complication-b">
-          <option value="none">         (none)</option>
+          <option value="none" selected>(none)</option>
           <option value="date">         date</option>
           <option value="weekday">      weekday</option>
           <option value="calendar-week">calendar week</option>
@@ -491,7 +712,7 @@
     <tr>
       <td></td>
       <td>custom URL:</td>
-      <td><input type="url" id="complication-b-custom-url"></td>
+      <td><input type="url" id="complication-b-custom-url" size="50"></td>
     </tr>
 
     <tr>
@@ -501,7 +722,7 @@
       <td> Complication:</td>
       <td>
         <select id="complication-br">
-          <option value="none">         (none)</option>
+          <option value="none" selected>(none)</option>
           <option value="date">         date</option>
           <option value="weekday">      weekday</option>
           <option value="calendar-week">calendar week</option>
@@ -513,7 +734,7 @@
     <tr>
       <td></td>
       <td>custom URL:</td>
-      <td><input type="url" id="complication-br-custom-url"></td>
+      <td><input type="url" id="complication-br-custom-url" size="50"></td>
     </tr>
   </tbody></table>
 </p>
@@ -527,26 +748,11 @@
   Here you may specify these colors. Click on a color to select it - or on
   "themed" if you want the clock to use the currently configured theme on
   your Bangle.js 2:
-</p><p>
-  <b>Foreground Color:</b>
-</p><p>
-  <label class="ColorPatch">
-    <input type="radio" name="foreground" value="Theme"/>
-    <span>themed</span>
-  </label>
-  <input type="radio" name="foreground" value="#000000" class="ColorPatch" style="background:#000000"/>
-  <input type="radio" name="foreground" value="#FF0000" class="ColorPatch" style="background:#FF0000"/>
-  <input type="radio" name="foreground" value="#00FF00" class="ColorPatch" style="background:#00FF00"/>
-  <input type="radio" name="foreground" value="#0000FF" class="ColorPatch" style="background:#0000FF"/>
-  <input type="radio" name="foreground" value="#FFFF00" class="ColorPatch" style="background:#FFFF00"/>
-  <input type="radio" name="foreground" value="#FF00FF" class="ColorPatch" style="background:#FF00FF"/>
-  <input type="radio" name="foreground" value="#00FFFF" class="ColorPatch" style="background:#00FFFF"/>
-  <input type="radio" name="foreground" value="#FFFFFF" class="ColorPatch" style="background:#FFFFFF"/>
 </p><p>
   <b>Background Color:</b>
 </p><p>
   <label class="ColorPatch">
-    <input type="radio" name="background" value="Theme"/>
+    <input type="radio" name="background" value="Theme" checked/>
     <span>themed</span>
   </label>
   <input type="radio" name="background" value="#000000" class="ColorPatch" style="background:#000000"/>
@@ -557,12 +763,29 @@
   <input type="radio" name="background" value="#FF00FF" class="ColorPatch" style="background:#FF00FF"/>
   <input type="radio" name="background" value="#00FFFF" class="ColorPatch" style="background:#00FFFF"/>
   <input type="radio" name="background" value="#FFFFFF" class="ColorPatch" style="background:#FFFFFF"/>
+</p><p>
+  <b>Foreground Color:</b>
+</p><p>
+  <label class="ColorPatch">
+    <input type="radio" name="foreground" value="Theme" checked/>
+    <span>themed</span>
+  </label>
+  <input type="radio" name="foreground" value="#000000" class="ColorPatch" style="background:#000000"/>
+  <input type="radio" name="foreground" value="#FF0000" class="ColorPatch" style="background:#FF0000"/>
+  <input type="radio" name="foreground" value="#00FF00" class="ColorPatch" style="background:#00FF00"/>
+  <input type="radio" name="foreground" value="#0000FF" class="ColorPatch" style="background:#0000FF"/>
+  <input type="radio" name="foreground" value="#FFFF00" class="ColorPatch" style="background:#FFFF00"/>
+  <input type="radio" name="foreground" value="#FF00FF" class="ColorPatch" style="background:#FF00FF"/>
+  <input type="radio" name="foreground" value="#00FFFF" class="ColorPatch" style="background:#00FFFF"/>
+  <input type="radio" name="foreground" value="#FFFFFF" class="ColorPatch" style="background:#FFFFFF"/>
 </p><p>
   When you are satisfied with your configuration, just click on "Upload" in
   order to generate the specified clock and upload it to your Bangle.js 2:
-</p><p>
-  <button>Upload</button>
 </p>
+  <p id="MessageView" style="display:none; color:red"></p>
+
+  <button id="UploadButton">Upload</button>
+</p><p> &nbsp; </p>
  </body>
 </html>