I've been trying this technique for a few weeks now. I haven't noticed any change in my playing, good or bad. Now, I have my thumb stupidly hanging in the air doing nothing. There is no use for it. It feels and looks dumb. It feels very uncomfortable too, and it gets annoying to mute strings with my pinky. I also have the feeling that string skipping is way easier and more accurate with a thumb solidly anchored on the pickup. I'm back to normality, thumb solidly anchored, 3 finger plucking and pinky muting. What's your experience with it ?