While the Grimoire is left to ferment, I can work on the CAT. I'm going to rename it to the "Porta-CAT". Just sounds better.

Currently, the low profile switches fit perfectly into the 14mm holes, but they make the whole thing too tall. I want to be able to close this up in an Altoid(ish) tin for protection. So it needs to be shorter.

I've modeled a version that is shorter (about 18mm). I also squeezed the sides in a tiny bit, then added some spring tabs to allow it to be inserted and removed (for possible repairs in the future).

You can see the tabs there. What you can't see is that I changed the holes from 14x14mm to 12x12mm. Which means we can't use regular keyswitches. Luckily, I found some nifty 12x12x7.5mm buttons at Adafruit. They also have some round ones, but I think those will be too tall (12mm).

The holes in the bottom of the wells there are for the prongs on the buttons. I have made the bottom panel of those wells 1mm thick. I think the prongs will fit through that, and can be soldered on the other side. From that point, it's just a matter of some short wires to the Pro Micro, then the USB cable, and we're golden.

The next step is to print this insert to test the size and the tabs. Then we can order the buttons and test fit them. I'd rather have the buttons so I can measure the prongs before printing, but I'll see if I can finagle it. I have some ideas...