Jim … you made an excellent post above.
Want to follow-up and solicit further critique.
When I attempt to accentuate the bending of the spine near the L2/L3 region … during the portion of the swing where we see the ‘lateral tilt’ of the shoulders … then the reactionary feel for me is that of the upper rear leg driving … and rotation is observed. I am rotated, yet not actively attempting to rotate. My hip leads, largely as a result of that spine action in conjunction with the synchronization of the swing.