It's a pointless exercise. Consider the physics of it. F=ma and F=-kv (so the force of resistance is proportionate to the velocity, where the constant, k, represents that coefficient of resistance) are the two equations we're most concerned with here. By reducing the ball size we reduce the force of air resistance and drag on the surface area of the ball in flight, which is good. However, if we reduce the size and are using the same fills/materials, the ball will be lighter, which means the force on it will have a greater effect (F=ma) which at best means the flight path will be similar, rather than longer and less arced. Also, because of a smaller surface area there will be a greater force on impact, which means they'll hurt more -> potential reduction in velocity. I don't think the benefits outweigh the costs tbh, but these are pretty basic calculations so for all I know they could be infinitely more accurate and amazing.