Having a list of materials and measurements made by a contributor would get you within the ballpark, I suppose, but is pretty useless in my opinion. The above post by Scota 4570 is an example. The measurement I need is the fully compressed dimension, as if the material was squeezed between the ball and the bore. What is rebounds to is irrelevant. But I'm sure it works for him. His numbers would be meaningless to me.
The process of selecting patch material fabric is very easy and simple, but you need to have the material, and a measuring device, in hand. Once you have done that and recorded the ounce weight, you might be able to take a chance on ordering material on-line. But surely fabric stores are not that scarce.