Lets not forget when the arms stay within the radius of the shoulders it will be different for different body types. Broad shoulders have more room to stay connected than say thin or slender folks.
Also, while the shoulders initiate the backswing, some folks overdo it. While the back to the target concept is good, some folks overdo that too.
I guess there should be no extremes in golf but its human nature to think if one pill is good, two are better; not true in golf or hardly anything else either.
Hitting against a firm right hand with the back of the left hand pointing at the target means the right hand should at least be palm facing target depending.
Unlike some gimmicks, it is not necessary to try to time the release; if the grip is sound, release will come naturally. Overdo the grip and you will overdo the release; underdo the grip and you will limit the release. Anyway its nothing you should try to time; may work on the range but it won't hold up on the course.