Could you please expand on your belief that the clubshaft rotates about the COG of the clubhead?
When I swing a golf club or a hockey stick across the front of my torso, I can see the clubface closing so that the toe of the club eventually passes the heel. I can also see that the clubshaft hosel has a rounded arc motion. However, I cannot see the clubshaft rotating around the COG of the clubhead. Where should I be looking to see that phenomenon happening?