Very nice podunk. I am also trying to build a similar device. I have a few questions.
1. How do you install actuators and get them to stay in? I was thinking of these
Stainless Steel Tact Buttons
2. Do you need to insulate the negative battery connections? Looks like you used the brass end piece to complete circuit.
3. Is 18g wire ok to parallel batteries?
I believe you this will be a PITA to put together, so far ive only done a hammond box with dna 40 so this should be interesting.