I was thinking about if I should play with a 4 1/4 grip size for slightly more spin or 4 3/8, which is technically the correct size for me. Then I did a thought experiment about if the actual size matters, other than for comfort. Lets say you have really tiny hands, such that a grip that is the thickness of a pencil is perfect for you (but the racket is usual size). When you hit the ball, I would think that the racket would twist a lot. On the other hand, if you a hand that is a meter long, it would be really really sturdy. These are the extremes...but would there really be this recognizable a difference between 4 1/4 and, say, 4 1/2?