I have trouble with my left middle finger (the left ring finger also but to a much lesser extent), and want to reduce the amount of up/down motion on those fingers, especially in cases where just that finger moves up or down rather than the whole hand (e.g. typing ES or CR on QWERTY -- in fact anything with a C in it).
I've started learning colemak (via tarmak -- working well for me so far but only on Tarmak2 so far) because it makes more use of the home keys than most layouts -- but of course specifically F and C are still common letters so I'd rather have them elsewhere.
By the way, for reasons somewhat unconnected with my finger problems I'm using an ortholinear keyboard -- so I can't hit the C with my index finger.
I've been considering swapping F with Q and C with V, or maybe even C with Z. The C I think is worse for me than the F both because of the higher letter frequency and because when moving down, it tends to be just that finger rather than the whole hand. FA and AF are not terribly common, so I guess the F/Q swap isn't too bad? For the C, I think I could live with having to hit that position for V, which is about three times less common, but it's not ideal. Of course the C/Z switch is appealing because of the very low frequency of Z, but I notice that the CA and AC bigrams in particular are fairly common. A C/X swap, though also appealing on the letter frequency and same-finger bigram basis (CR is surprisingly uncommon), would use my ring finger, and I'd rather avoid the single-finger-down motion for that finger for the relatively common letter C. I can't see anything obvious on the right hand side of the keyboard that would work as a good swap for C on the basis of letter and bigrams frequencies.
But maybe I'm not thinking big enough and a bigger reoptimisation is worthwhile? For example, maybe I'm missing some crazier multi-key switcharound that while worse than colemak for most people, would work for me? Are there any layouts that cater specifically to people with problems with particular fingers? Has anybody done any work on that? I know carpalx exists, but I'm not sure if the model caters for my sort of problem? Any comments on the key swaps I'm considering? Am I missing important factors apart from same-finger bigrams?
Thanks for your help!