So we're meant to push with the right arm around mid-way down the downswing (club vertical to ground, face-on view) for full power. How are you meant to time this? Is it more of a gradual thrust or sudden push?
Also, after experimenting a bit with this, I figured to achieve consistency (in feel) across all shots/clubs, I also need a bit of right arm thrust for half swing pitch shots, even though less than full power is needed. What do you guys think?
Good question, tongzilla ... and as a matter of fact, I did offer a forum question for the ASII scientific panel on the application of "out-toss" as it may affect downswing shaft loading patterns. I haven't heard any response, or even if the question was presented to them.
Nevertheless, the timing of the use of the rear arm/hand against the club handle in the downswing does create unique downswing shaft loading profiles as revealed by True Temper in their ShaftLab apparatus which measures that loading.
Here are three graphs of typical downswing shaft loading profiles as determined from TrueTemper ShaftLab testing.
The scientific study backing up these curves is in Science and Golf II (1994): The Dynamic Performance of the Golf Shaft During the Downswing - J.H. Butler and D.C. Winfield
As you can see from these load curves, the shaft loading can be one-peak, two-peak and ramp-up. The application of force on the handle contributes to the loading of the shaft, and we can see from the curves that rear hand loading can be early, late or intermediate within the downswing.
Everybody has a different style of shaft loading, and there can even be hybrid loading profiles. Unfortunately, TT has discontinued their neat ShaftLab gizmo because it was expensive, there was little interest by "feel" golfers and the strain gauges within the shaft tended to fail with no easy repair.
Interestingly, there is no one "best" loading profile, and the graphs for pro golfers varied across the spectrum. So asking when you should apply "right" arm force on the club handle that is quite personal. Now that you are aware of how shafts can be loaded, it may assist you in guessing how you prefer to load the shaft in the downswing, and then take it from there.