[Yoda]

1. It is possible for the top of the Swing Center Hinge Pin to be located anywhere -- extreme left, extreme right, extreme forward, extreme back, and anywhere in between -- with the bottom of the hinge pin precisely between the feet. Therefore, the concept of the Swing Center Hinge Pin seeks only a stationary head but does not mandate that the head be in any particular location.

I agree (and have stated several times in posts) that it is not mandatory for the player to locate the Head -- either at Address or at Impact -- "precisely between the feet" in order to establish a Pivot Center. However, having located the Head (and thus establishing the Pivot Center), it is important that its position be maintained.

Personally, I visualize the Pivot Center Hinge Pin as being perpendicular to the ground, regardless of Head position. Thus, the Hinge Pin would fall "precisely between the feet" only if the Head were so located.