As a full time developer who used to suffer terrible RSI pain, I solved the problem without changing keyboard layouts. After consulting with my doctor and an ergonomics expert, I realized my problems were cause by the setup of my workstation and the bad posture habits I had developed.

1. I would rest my palms as I typed. This turned out to be a major source of pain. Retraining myself to "float" my hands over the keyboard was a massive improvement.

2. My desk was too high / my chair was too low. Setting up my desk so that my keyboard is as close to my lap as possible was the next big improvement. When in a seated position, my hands are very comfortable when resting on my thighs. Putting my keyboard in a drawer that is just above my thighs helped a lot.

3. I also switched to a trackpad instead of a mount and a split keyboard. I found this allowed a more comfortable angle for my hands and less temptation to rest my wrist while mousing.

After making these changes, I have been pain free for over 10 years.