Re: Understanding "decoupling"
Dan, did you actually watch the videos on circle walking you cited? In the first, Kent Howard Sifu does, in fact, move from heel to toe as he circle walks. In the second, Eli Montaigue Sifu, does not and contradicts Howard Sifu, both physically and orally. I call your attention to 1:47 and 9:50 of Montaaigue Sifu's video where he is emphatic about not rocking forward to the toes. Your cited point at 5:57 had absolutely nothing to do with the vertical orientation of the foot, but rather placing the toe in a specific position along the circumferance of the circle.
I don't practice baqua and have only watched a few videos of the circle walking, but all the others I've watched have emphasized keeping the foot flat as it lands on the ground. This small inconsistancy causes me to doubt your credibility concerning your concepts, but I eagarly await your next posting as it may explain the things I find concerning in the first two.
All that said, I do appreciate the effort you are making here.