dactyl-manuform-keymap VS qmk_firmware

Regarding chording, you might find inspiration in the chording schemes in Ikcelaks’ Magic Sturdy, the Ardux project, and precondition's "steno-lite" combos.

I spent most of the last 2 years using variants of this but more recently I’ve switch from home row mods to one shot mods and modifier positions similar to Xah. https://github.com/precondition/dactyl-manuform-keymap

Something that made a big difference for me was home row mods. If you can use QMK to embed ctrl, shift, alt, gui into ‘long press’ on the home row it will reduce strain from overusing the pinky finger. After about 1 year of using a variation of this setup I think home row mods reducing pinky finger strain has been the most noticeable improvement although there are many more benefits to switching to something like this dactyl manuform kb. https://github.com/precondition/dactyl-manuform-keymap

How did I arrive to this keymap? It's been a journey. I used home row mods for a few months. This felt great, but with my sloppy typing I routinely got false triggers (despite IGNORE_MOD_TAP_INTERRUPT) and struggled to get my typing speed much above 60 wpm. ​In an attempt to reduce false triggers, I wrote my own (not very good) mod-tap implementation, then realized this is a hard problem. I tried Precondition "steno lite" (see the system of combos in his keymap), and worked through some lessons from Zack Brown's excellent Learn Plover site to learn a little about real steno. I've dabbled with RSTHD and BEAKL15 before going back to Dvorak.

Combined with its separate hold behavior and some tap dancing on them in other layers, these keys does so much that I sometimes doubt it would all be possible with just two keys.

My layout has 34 keys and is optimized for software programming, with symbols spread across two layers, on the left side of the lower and on the right side of the raise layer, so you can reach all symbols with a single hand. It might worth checking if it fits your case, and you can always reposition the symbols according to your needs.

I use my BM40 as a daily driver for a few months now, also with a split layout.

I use a 34 keys layout in my planck, and put the symbols in the left side of the lower and right side of the raise layers, so that I can access them with a single hand, which for me feels more intuitive. < and > goes in the same positions as comma and dot, so I can also access them using shift, which I use mostly for indentation in VIM. {, (, [ and < are in the middle finger columns, above and below the home row, which makes them easier to access. The closing counterpart are not used so often, since the text editors type them automatically, so it is okay to improve for the position of the opening counterpart.

This is really nice. Thanks for sharing. I plan to do the same in the future with mine, but it still needs some cleaning and documentation.

I use keyboard-layout-editor.com to maintain my visual keymap and update the keymap.c manually, but formatting the code and comments to make it easier to read and edit. I've tried something like you are doing, but it did not worth it.

I'm a VIM user, but I rather use j as the left arrow instead of h, to avoid lateral movement, so I disabled hjkl in VIM and use my navigation layer instead, holding the left thumb. I use a lot of layers, but everything is easy to reach and remember. I also use a combo to activate the navigation layer using only the right hand. https://github.com/rafaelromao/qmk_firmware/tree/rafaelromao/keyboards/kprepublic/bm40hsrgb/keymaps/rafaelromao