[Mike O]

Mike

I think that you are correct to bring up the issue as to whether the clubface being square to the arc during the immediate post-impact period represents angled hinging. I would agree with you on this point. Do you also think that the clubface remains square to the clubhead arc for the entire duration of the followthrough, until the finish swivel action commences? A) your still assuming angled hinging and not horizontal and vertical and B) I would say depends - anything is possible- so doesn't have to. I also presume that the timing of the beginning of the finish swivel action (and therefore the duration of the followthrough phase of the swing) varies from golfer-to-golfer. Do you think that Hogan had a followthrough phase that was shorter, or longer, than usual? A) varies from golfer to golfer and B) it's that point where the hands get opposite the middle of the chest - where both arms are straight- so depends on the relative amount of pivot rotation in relation to arm movement.
Finally, Dariusz also wrote-: "Hogan delivered his clubface square already before entering the impact zone and maintained it square long after impact what is one of very suspected "culprits" of his overhuman accuracy and repeatability."

That sentence implies that Hogan's clubface was square to the clubhead arc well before impact. Surely, that cannot be true with respect to TGM teaching, which implies that the clubface must be slightly open at the time of first ball contact, and square at the exact moment of ball-clubface separation for the ball to go straight? That TGM concept means that the clubface must approach the ball with an open clubface in the few inches prior to impact, and that it cannot already be square to the clubhead arc before entering the impact zone. What do you think? Depends on the type of hinging being used- I wouldn't see it as a problem or anti TGM.
Finally, in terms of hitting the ball consistently/reliably straight, is there evidence that horizontal hinging is better/worse than angled hinging NO (ignoring the fact that horizontal hinging predisposes to a draw at the end of its straight ball flight, while angled hinging predisposes to a fade at the end of its straight ball flight)? Horizontal hinging does not predispose to a draw.
Jeff.

My quick comments above- too tired to post more now.