I've experimented with putting some or all of my modifier keys under non-pinky keys like O on my ergodox. My problem with that is that it forces me to drastically slow down my typing. Otherwise typing a word like "word" will register as 'w ctrl-r d'.

I have not found a timeout value that will always register "word" when I'm typing at 110wpm and also Ctrl-r when I'm just lazily hitting that single hotkey :/ It's either too fast or too slow for some use cases.

I have read some posts from people that use layouts like that and it either seems they already type pretty slowly or they have RSI problems and it is worth it to them to slow down.