i have learned to controll my fingers to move as little as possible. but i have failed to keep my pinky within less than 2-3 cm. but.. it does not slow me down the slightest bit. my pinky is fast enough to overcome that distance in time when necessary. so i dont work on it anymore. 16ths at about 220 bpm is fast enough for me. i dont realy want to go any faster for i can´t think of a solo where that makes essencial sence.