JS: Three things helped me stop over rotating:
1) consciously try to slow down the rotation of your entire spin. It is really hard to stop a spin at 180, so once you get turned about 120 degrees, just sit tight and let it develop on its own;
2) start your spin a little farther out from the wake (your distance from the boat looks fine). It feels like to me that the more you start your spin up the wake, the faster it wants to turn;
3) I had a tendency to lean over too much - I find I do better if I think "squat down centered on the board" rather than "lean over my toes" I think it relates to what Curt suggested - it is easier to stop rotating if you are more centered than if your upper body has developed a lot of rotational movement.
Not sure any of these will help. It may be that what really helped me was just failing over and over again to get it, and these were just the thoughts I was trying at the time I finally started getting it. Hope they help. It's worth the satisfaction to keep working at it. Rob