Youtube channels mfranssila and channel lcgm8 especially seven drives with Avery Jenkins are a start for vids. lcgm8 has drive comparisons in slo mo in Tali Open 2009 and 2011 plus check put the goodies in the Scandinavian Open 2010. Check out Paige Pierce in President's Cup 2011.
Using feather light steps with each of them landing only on the balls of the feet (unless the final step is toe to heel to toe) should help with the rear heel being off of the ground. That may need more muscle tension in the plant of the x step in the calf. Sound funny feather light and more tension but it is doable. The lightness comes from gliding smooth motions not so much jerking accelerations and hopping up high and crashing down hard. The legs should glide low parallel to the ground for lightness of steps and the rhythm of the steps is a major part in form. Timing and stuff.
Beginning of understanding athletic position roughly according to David Feldberg: Stand with feet parallel on a line from the basket and jump up and turn 90 degrees to face the basket. The position you're at should be athletic position. But more suitable for putting than driving. Any athletic position should be balanced. It shouldn't be easy to push you to fall.
Stopping the arm drill: Standing back to the wall throwing arm raised to shoulder height moving to a corner to allow the wrist to move freely start making super low powered throws. Elbow braces are good to use. The wall will stop your arm and the momentum, will snap your wrist to hyper spin position from momentum. If you stop the wrist abruptly with muscle power before reaching maximum extension (never do that as it can ruin your tendons for life and have you in agony for the rest of your life) the disc will continue with the momentum. If you pinch long enough=HAAAAARD! the disc will pivot fully. Increasing speed and spin. A round house shoulder socket driven non stopping motion won't achieve that lightning fast (faster than muscles can provide) wrist snap.
Not leaning toward the back of the tee will drop the nose dramatically. Standing up helps with getting the nose down but a little forward leaning can be a good thing for low ceiling shots and learning to keep the nose down. Pushing the thumb as far forward as possible will reduce grip strength but with enough power applied until the rip can push the nose forward. Just before the rip pushing down of the wrist can help too and that may need a lot of muscle power. Working out.
If you have a flexible and fluidly moving neck the head may not hurt the throw. As long as your hips move left enough in the reach back and right enough at the rip and very far in the follow through. From the hips up you should resemble a clockwise turned cork screw with max powered throws. Check out how far Markus Källström twists the hips to the right at high power levels.
Shoulder positions. The drill above and rereading about the pause.

