I recently upgraded the manuals and thumb pistons in my own console to have a full set of features that can work with various VPO packages I own, including Organteq.

If you'll forgive my linking to a different discussion forum, you may find the discussion of various perspectives about thumb pistons useful:

https://organforum.com/forums/forum/org...mendations

My final layout is probably way overkill for your application but perhaps you can get some ideas.

I've also made the Photoshop template I developed for experimenting with layouts available to anyone who'd like to give it a try:

https://www.bobrichardson.com/a-diy-thu...n-project/

I'm curious about your left/right touch screen approach - how are you dividing up the one Organteq window?  Or have you come up with a separate user interface that communicates with Organteq over MIDI?  (I've been working up my own set of suggestions to Modartt on how they might support multi-monitors and touchscreens.)