I still don't understand what you mean by 'trail hand below'. In 'racing round' from 6/100s to reverse mirror the trail hand follows the shaft so it starts (hopefully) on level with or above (vertically higher) the lead hand, goes below (vertically lower) and then goes to slightly above (higher bertically).
I also don't know which question from petearm you mean relative to this.
I was only implying 2-D in my comment (though it is of course 3-D). In plane you still have the issue of the dynamics of the swing overcomming the retaining force.
There is no explicit active rotation of the lower body in Bertholy. THere is the motion initiated by the moving of the lead knee and that starts BEFORE the drop. In the photos of Player and Hogan the hip rotation has taken their hips to parallel to the target line at the point where the drop is complete. And the forward whift is explitily 'caught' on the lead leg.
