Single Wrist Action Procedures

[Par71]

I might be a bit slow to understand this:

10-18-C. SINGLE Here, the Left Wrist is Cocked but not Turned. The Action has three alternative procedures:

1. Let the Pivot bring Horizontal Hinging to a normal On Plane "Top" position.
2. Let the Pivot bring Angled Hinging to a normal On Plane "Top" position.
3. Hold the Wrist "Vertical" throughout for a True Single Action "Top" position.

Could someone please explain these three alternative procedures in more detail? What are the proper alignments for the wrists, the clubface and the shaft with each of them during various stages of the Backstroke?

Is the Top position identical for the #1 and #2 procedures? What does the "True Single Action Top position" of that #3 procedure look like?

How does Hinging on the Backstroke work anyway? Is the hinge pin still your left shoulder?

Would the #1 procedure (Horizontal Hinging to a normal On Plane "Top" position) still be a Hitter's procedure? Or would this rather be the choice of a Swinger who for some reason decides to use Single Wrist Action on the Backstroke instead of Standard Wrist Action?