The definition or description of being "On Plane" I usually hear is... one end of the club or the other is either pointing to the plane line or parallel to that line.
What percentage of pros do you think actually comply with this definition on the BACKSWING? They are all obviously doing this on the DOWNSWING, or at least during the later stages(or very close to this).
Do you believe there are some VARIATIONS where being off plane, by this definition, on the BACKSWING is actually correct?