[nevermind]

Tong? Anyone?

Without giving up on having the above questions answered, I've got some more.

Questions so far have been in relation to a golfer with a zero shift downstroke on the TSP, now for one where the golfer shifts the clubshaft down to a flatter plane during the Downstroke. In that case, how long should you aim to keep the trail shoulder moving down plane(TSP)? Without a clue on the "how long", my guess is that golfers shifting down to a flatter clubshaft plane are likely to keep the trail shoulder going downplane(TSP) further into the Downstroke than those with the club on the TSP. Is that way off?

This is my understanding as it stands, still some work to be done. Ready to admit I'm prolly a long way from having a firm grasp on this.
When using the TSP on the Downstroke, you will almost certainly have the trail shoulder moving above plane before impact. That allows (or is it just coincidence?) the trail forearm to be on plane at impact without having a straight trail arm.
When using a flatter clubshaft plane, you can have the shoulder move down plane(TSP) all the way to impact and beyond and still have the trail forearm on plane with the shaft at impact with some elbow bend.