I use space2ctrl ( https://github.com/r0adrunner/Space2Ctrl ) which makes the space bar act as Ctrl when used as a modifier. It can occasionally turn the first letter of a word (eg. "hello") into a shortcut (eg. "Ctrl-H" ello) and prevents me holding down space to get lots of spaces, but that's what Alt-number is for. It's been the most effective way to reduce my Emacs pinky. I still map Caps Lock to Ctrl, so I can do Ctrl-Space to mark.
