[JerryG]

Since they are Henry's tennis balls they are his favorite color, the color of dirt.
As for being large, that's the point. It helps to visualize the angle of attack on the ball. I like to think of it as at 2:00 o'clock with the top of the ball being 12:00 and the bottom being 6:00.
I spent over 50 years being a scooper. I need things like this.

I'm willing to try most everything. But isn't it strange to hit such big balls? (Do you use white tennis balls or the yellow ones?)