Gumshoe

One thing I noticed is some of the case are labeled row x column and some column x row. I believe the standard is row x column, so the cornes, for example, should be 3x6.

right hand pain.

Any sense for what is different between your hands? You sure this isn't a mouse issue?

What kind of motions cause the pain?

There are 3 basic types of wrist motions rotating along each axis. Potentially you're either doing a lot of motion in one of these categories or your normal resting position isn't neutral in one of these categories. Maybe try to figure out which of these motions/positions is causing you issues and come up with ways to try to cut back on that motion or position the keyboard more neutrally in that axis.

Also, you should look into doing exercises to help with your issue.

No, you can setup a dongle with bluetooth. In a regular zmk setup with nice!nanos or whatever bluetooth MCU, the two halves communicate wirelessly over bluetooth, a central one that does all the calculating of what key presses to actually send, and a peripheral that just sends raw keystrokes to the central one. But with a dongle setup, you'd get a 3rd MCU that you plug into the computer that acts as a central board without any keys that has 2 peripheral boards it communicates with. Because you'll keep that 3rd MCU plugged into the computer, it won't need its own battery or even any components, it can just be a bare MCU. You could also make a case for it if you wanted:

https://www.youtube.com/watch?v=YwsutNf1WRA&t=721s

Or get a 3rd MCU to use as a dongle so that acts as the more power hungry central board. Even with tiny 110mAh batteries, that'll give you 3 months of battery life with a pair of nice!nano2s.

You're kinda all over the board on which keyboards you're looking at, 36 to 80 key keyboards, some with keywells, some without, some by big companies, some open source made by solo vendors. If you're looking for just a list of keyboards to browse through, you can checkout the wiki here and focus on vendors in your region: https://gitlab.com/ergomechkeyboards/wiki/-/wikis/useful-resources. If you're looking for recommendations, you'll probably need to give us more than just something to travel with.

I would say that keywells don't make for very travel friendly boards. If you want a big company build (OEM), I think the ZSA lineup (ergodox, moonlander, voyager) are going to be the best travel boards. If you're looking at open source boards (corne, skeletyl, etc - DIY boards, they're called, but you can find solo vendors to do the complete build for you), then pretty much any flat board you find will be better to travel with than a skeletyl or glove80, and from there you can choose as many or as few keys as you want. For either DIY or OEM boards, I would just browse the list of vendors in the wiki link I posted above.

My thought was if this would be able to be controlled on a regular MX switch and if such a program already exists?

No. Most MX switches feature a mechanical switch that moves actual metal pieces to complete a physical circuit by coming into contact with each other at the actuation point. It has neither the ability to detect where in the keystroke it is nor alter the point at which the metal pieces make contact.

I say "most" because there is a thing called an "optical switch" which can have this type of capability, and they DO make this in an MX form factor, but you can't just use these in any MX compatable board, it would need to be a board designed to work with optical MX switches.

How much of this was soldered by you vs the pcb manufacture? Boards without a separate MCU have always fascinated me, but I haven't been able to price one out because haven't been able to figure out how to use JLBPCP's pcb assembly service.

I think this is the most keys I've seen crammed into such a low-pin controller. Did you have to do anything special to get the whole matrix in there?

It could take a lot of shapes. It could look like https://www.beeraider.com/one-handed-keyboard/ or https://tipykeyboard.com/en/?v=fa868488740a or you could check out the split keyboards here with 80+ keys https://jhelvy.shinyapps.io/splitkbcompare/

There are a few different options, though none of them are without trade-offs.

1. You could try getting a pointing device integrated into your keyboard, like a trackpad, trackpoint, or trackball that could be used with a single finger while the rest of the fingers are more or less still in the home position. For example, a tractyl.
2. You configure your left hand side (assuming you mouse with the right) to have extra layers which give access to a full keyboard from just that hand. The first thing I would do here is figure out how much you really need to access... Do you just need copy/paste/cut? Do you just need alpha keys? Do you really need a full keyboard including symbols and alt, F-keys, etc? For an extreme version of this, this keyboard using a Taipo layout gives either hand access to a FULL keyboard with only 11 keys per hand, and you have almost 3 times as many keys to work with. You can type entirely with just the left side or entirely with just the right side with that keyboard, though going that small will have a steep learning curve.
3. Get something with even more keys than a sofle, but for just the left split, and you'd only use those extra keys while one handed typing, so each one of those keys is a duplicate function that can be achieved in a different way when you're using both hands. You could even use a 60% keyboard as your left split, as it would mostly just invade the space between the keyboards which you might have free due to the split.

The most popular 36 key layout is probably miryoku. It uses home row mods for ctrl, shift, etc. A lot of people start with this layout out of the box and then customize from there.

The way the pinky row meets your pinky in the final picture is really satisfying. Its hard to tell using just the last picture, but I think your typing position has your fingers a bit more extended than mine and your typing, while still largely with the tips of your fingers, I'm even closer to the direct tips than you are with more finger curl while typing.

If I do the same smiley-face exercise, I only get the smiley-face if I don't bend my knuckles very far. As I curl my fingers in more towards either my knuckles or center of my hand, the smiley face disappears and even eventually inverts (though that inversion happens far past what would be comfortable for typing). The amount of curl I have for my normal typing is pretty neutral and doesn't really make the smiley face.