As Brian has pointed out, the
hands reach their max velocity well before impact... and that also means increasing centripetal force to "go normal" when you are in final release. I believe you shouldn't be wanting to turn the grip fully over at this point otherwise you are probably handle dragging and boxing yourself into consciously flipping. The gamma torque that contributes to squaring the clubface should have done most of it's work by then.
Calm down when the club passes your right leg and just concentrate on continuing your shoulder rotation and going normal, naturally. Applying parametric acceleration by jumping may just complicate things in final release to impact, so you can omit it ... as I believe Brian suggests too. Once you have the golfswing basics down pat, you might try juicing up your swing with parametric extension of your left leg.
Everything in good measure ....