I did some back of the envelope calculations for fun. A 5-key setup would allow one-hit triggers of: abcdefghijklmnopqrstuvwxyz and space, period, apostrophe,

I did some back of the envelope calculations for fun. A 5-key setup would allow one-hit triggers of: abcdefghijklmnopqrstuvwxyz and space, period, apostrophe, enter. Then add a "shift" key and you add one-hit triggers of A-Z, backspace, question mark, tab, esc. Then you could get 60 additional output values with double-tap shift and hold + key (30) and double-tap shift and release + key (30).