getting a video of oneself is the first step to curing any ills. my teacher way back when videoed us and also fast forwarded mine once. i looked like a wind-up toy that went forwards and back with my torso. so, then, after that - i tried to be much more careful of how much i was going back and forth. never keep time with the music with any part of your body.
whatever movements facilitate your hands moving around is probably better than what helps your head move around. there are a lot of head back - look at the ceiling type movements (which may release tension in the neck). but, other major movements (elbows out, etc) are just plain unhelpful to your playing, right?
i think helene grimaud occasionally looks up -except unlike chopin , she looks to the right. if i remember right.