I actually think his plane line on the backstroke is closed which normally causes a short pivot at the top of his backstroke but he then uses his pivot to readjust the plane line which is why his stroke looks slower than it actually is.
Mathew and lagster thanks for your replies. In Freddy's book he basically says that he sets up a shade open to offset his inside swing path grip and that allows him the whip his wrists through with no fear of a duck hook, worst case is a slight block right.
Seems to work best with a lazy tempo, and just letting the arms kind of drop from the sky as I fall back to my left heel. If I hurry anything and dont make a full turn I usually cast and hit it fat or hook it badly. When done right its a beautiful thing.