I use Colemak-DH and learned it through the Tarmak progression. RSI is probably the wrong reason to learn Colemak. It made little difference for me and as far as I know there is no scientific evidence that it helps.

Better: get an adjustable table and chair and ensure that they are correctly configured. Take regular breaks and do exercises. Get a keyboard that is split (to ensure that your wrists are not bent) and tented (to put our wrists at a more comfortable angle). Bonus points for column stagger. For me, switching to a Kinesis Advantage improved a lot to the point where I pretty much pain free.

(IANAD, but personal experience.)