(David Furman) Which Yardley book are you speaking of? My understanding of his writing's is that pitch has less effect on tightly held pre mounted trap guns where they use two beads set in a figure eight pattern. But, I understand less every day! As far as gun fit that covers all types of shooting, I think he is the most knowledgeable I have ever read. I think all your questions are answered in his books. He is one of the few who fit a gun and have you hitting without demanding you use his style of shooting. On the shotgun stocks I've had made pitch has had much more effect than comfort.
Tom Dulin