My instructor was a pincher. He said you have more control and will be more precise using two fingers. His analogy was, "Ever see any one thread a needle with a thumb?" Well I flew pinch style for years. Then when I got the "New" Dave Brown simulator and stated putting in hours of practice I found the thumb style to me more natural and more precise for me than pinching. I don't know if it's the geometry of my hands or if it's from the brain nerve connections established during 1,000's of hours of video games as a kid using my thumbs.