The grip completion has been discussed over the years, and my interpretation of the turning of the arms has been rejected. Jim, are you in the process of changing your mind or am I missreading you?
'Blake tried to convey the change action with figure 13 of GTTB. It shows both trail hand and forearm turning clockwise (from golfer's perspective).'
Fig 13 does not show any clockwise turn, only the somewhat conservative forward placement of the rear arm before the gripping of the club shaft. This part of the illustration has probably been a conundrum for anyone trying out the reflex swing.
My take on the grip completion is the same as it has been after the first bewildering years, and this is it:
After the gripping there is a counter clockwise turning of (a) the lead arm supported in doing so by (b) the rear arm and middle fingers, also turning counter clockwise. This is the only way you can actually shut the club blade in the backswing thus creating the convex lead wrist by letting the hands going outwards in the backswing.
Then, if you can maintain a really firm wrist through the ball your reflex swing will sore!
PS. Claude's practise exercises have been very helpful even if you think you are already doing the correct moves.