[Daryl]

This technique is exactly what you don't want.

The right hand rolls over the left after impact (not before and not during). Allowing the right hand to overtake the left before impact will always produce clubhead throwaway, with the typical bent left wrist. This is called a swivel impact and HK warned about that.

You can't practice or perform a drill on a horizontal plane that intersects the chest because the right elbow is not on plane and the Right Wrist will not overtake the Left Wrist after impact.

At Impact the Right Elbow is Bent. At full extension the right elbow is straight and will "Cause" the right hand to overtake the left (on an inclined plane).