Thumb Pad Over the Top

My understanding has always been that he meant thumb pad at the top of the shaft screwed left over the top. If you look at figure 23 in GSOTF this becomes obvious in that the V between thumb and forefinger of trail (right) hand (after screwing on of middle fingers) is pointing at the lead (left) shoulder. Interestingly, if you compare that with figure 6 in GTTB, the screwing on of the two middle fingers of trail (right) hand does not appear to be as extreme as in figure 23 of GSOTF. You can't see the knuckles on the back of his trail (right) hand in figure 6 as you can in figure 23. Jim