@ Dan

Thank you for your observations and comments.

I do have electronics skills. I have MIDIfied several large Organ consoles for use as virtual organs with Hauptwerk.

This version of the control surface is my cheap mock-up prototype. Once I am satsified with what I what to include and where I want to place it I will build a 'production' model

I agree that a touch screen or a 2 in 1 PC/Tablet that can drive the system would be a good approach. The cheap 12.1 inch display I have obtained is about the same width as a Microsoft Surface Pro 4 but it a little taller.

At this stage I think that a 4:3 screen aspect ratio is OK but 800x600 is not high enough resolution to show enough text on the vArranger on-screen buttons etc. I'll have a look around at the cheap open frame LCD touch screens but they tend to be only 800x600 pixels.

I also agree that illuminated buttons, synchronised to vArranger, would provide a much better view of the status of the software. I will use lit buttons on my final version but I just wanted to use the standard push buttons on the first propotype to get a feel for where each button should be and to work out the layout.

The buttons use a 16mm hole, so a spacing of one per 20 or so millimetres will probably be a suitable density.

If I reintroduce a Track Solo control then I think that I would only have one button for Soloing the Right1 voice.

I will be using a commercial MIDI encoder - not building/developing my own from an Arduino etc

Thank you for your offer to add missing controllers. Once I have settled on a final design I will let you know what I need. At this stage I'm quite sure that I will need:

* the Left 1,2,3; Right 1,2,3&4; 2nd voice and Bass Track Select controllers
- on the photo these are the nine buttons (1xyellow [Bass], 3xwhite [Left1,2,3], Red [Right1] 3xblue [Right2,3,4] and 1xgrey [2ndVoice]) on the bottom right of the picture above

* the ability to use buttons to select Right, Both or Left for the 'My Sounds' section
- on the photo these are the three vertical buttons (red, grey and white) to the right of the 20 Blue My Sounds buttons