Jeff, really there's not much to add to your two theories. I honestly feel you've hit the nail on the head.
Like you've mentioned no rest will help a shooter if the arrow is incorrectly spined, if a shotter has bad hand form (torque) and if their follow thru is absent, (holding steady).
Nevertheless, just like some bows, I too feel that some rests are more forgiving, to an extent.
You have already made mention of those circumstances in your thread above.
Keep 'em coming Jeff. I enjoy reading your educated thoughts
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