You mentioned Lee Trevino having tape over his left thumb. I also read your post on this subject "somewhere." The question is this: Was the purpose of this tape because his thumb was irritated or simply so he would have better feel with the #1 Pressure Point, whether he called it that or not.
I don't have large hands and I do have a problem putting pressure on that thumb . . . I can get it on #3, and it seems to be taking more pressure. But as hard as I push against the thumb, I can't really seem to really feel unusual pressure on it.