Here's the clamps holding the glue-up for the PCB mounting posts in place.

Last night and today I dealt with my home-crimped RJ9 wires being terrible by splicing on store bought DuPont connectors. This is janky but works. So I was able to get both halves working in concert today. Here's both halves wired up and all keys working.

Design problem 1: PCB Mount too fragile

Unfortunately I knocked one half off the table and the fall caused one of the PCB mount adhesives to fail (kind of expected) and one of the mounts to actually snap the PLA along a layer line (less expected). So that means the PCB mounting mechanism is too fragile I think. I may need to bolt all the way through the case or something. Not sure yet.

Design problem 2: DuPont and Crimping too fragile

My DIY DuPont connector crimps are bad. Many connectors are sliding backward out of the plastic housing because the "click" locking mechanism is janky. The DuPont are neat because they are slim enough to route through the same slots used for the keywells, but I think ultimately they just aren't going to be secure and robust. It kinda makes the whole build a bummer and at least right now I don't see a way to hack around this, especially not really how to salvage the keywells I've already built and the switches that are glued into them.