[EdZ]

During a swinger's backstroke left arm action, the left arm rotates clockwise so that an imaginary watchface on the left wrist would face the target at address, but eventually end up facing skywards at the top of the backstroke. I can imagine the left arm rotation i) occurring gradually throughout the backstroke, or ii) there can be a start-up swivel action that causes the imaginary watchface to face the ball-target line at the end of the takeaway (or be parallel to the inclined plane), followed by a more gradual left arm rotation during the remainder of the backstroke. Does it really matter which technique is used considering that the left arm must eventually have rotated to the same degree by the top of the backstroke?

This is ties into both right elbow position, and pivot motion (core trunk rotation). The key thing to keep in mind is that allowing that rotation is far better than 'making' it happen in my view.

If you delay the pivot, you'll feel more initial rotation (and more pitch elbow feeling), if you allow the pivot to move with the 'triangle', you'll feel less rotation, and tend to 'feel' more towards punch elbow. Hip action and knee action are also related.