[epistasis]

I don't understand your questions. What would touch typing have to do with it?

And you can still use right control when typing a letter with the left hand. When pressing control-<right-hand-letter> you have less stretching. I've subconsciously over time found that I mostly do single-handed cording with control-<left-hand-letter> though since the control location is so much more convenient than the shift location (for me). Your milage may vary!