[Yoda]

Does that mean that the whole hinging business is to put the FLW/clubface in the right position to obtain the hing action one wants - horizontal, vertical or angled.

The conceptually-mounted Shoulder Hinge Pin effectively moves into the Flat Left Wrist.

Accordingly, the Flat Left Wrist now duplicates the blade of a hinge moving perpendicularly to one of the Three Associated Planes: Horizontal, Angled, or Vertical.

I cannot imagine how I could put it more clearly, especially in the light of the afore-referenced videos, Parts I and II, filmed and posted here five years ago:

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C'mon guys. You've got to do the work.