I don’t “study” the golf magazines like I used to, but the March Golf Digest came today and has a one page review of Pasatiempo( MacKenzie), and a several page interview with John Jacobs…which is interesting. His opinion is that De Vicenzo and Woosnam had the most correct swings he had ever seen.
Later, along another thought, Jacobs said that the flat back, then slightly over has a lot to recommmend it, it is " a wonderful way to play golf badly." 
He didn’t like what he called the “rock and block”…the overly upright swing that came into vogue with Nicklaus and other Americans.