[Yoda]

... how much clubface motion could we expect with horizontal hinging for say 12 inches prior to impact point and 12 inches after separation? I'm thinking that maybe people have the clubface rotating TOO MUCH when using horizontal hinging (swivel vs. hinging).

Swingers typically execute Release as Standard Wrist Action (10-18-A). In other words, from Release to Impact, the Left Wrist executes an Uncock and Roll.

This Release Roll is a true Swivel -- independent Wrist Motion -- from Release to Impact. This is followed by a Hinge Action 'Roll' (the Left Wrist simply remaining vertical to one of the three associated Planes) from Impact to the end of the Follow-Through (Both Arms Straight position).

For a given Clubface executing Horizontal Hinge Action (Closing Only) about a constant Pivot Swing Center -- there can be only so many finite degrees of travel.