[ploversteno]

You really need a minimum of 16-key rollover to do steno properly. Otherwise you're just really constrained in the number of chords you're able to write.

[natch]

I believe you (hey, you are the expert!) but I wonder why is this the case? We only have 10 fingers, so how does 16 come into play?

[ploversteno]

Each finger can press up to two keys at a time (top row, bottom row, or both rows together). Right pinky can press up to four at a time (two rows plus two columns), and right index can press up to three at a time (two rows plus asterisk column).