I found this thread while looking for inspiration for my own 3d printing adventure and ended up reading the whole thing. Your panels are incredible. A lot of your solutions to switch mechanisms have given me lots of ideas.
I think I might have to upgrade my printer as seeing your ability to print at small tolerances has made my now aging AnyCubic's prints look dated.
Just one question, I know you're using DB9 connectors for the RS485 bus. How are the modules in the stacks connected together? I've seen the ports on the side, are you just lining up the ports as you design and build?