I missed this thread, Huvius, due to being at the lake (I assume). I'm glad it has been resurrected.

Hi Bill. For my paper ctgs. I just used normal bond paper, which would be in the 20 pound range. .003"/.004" or so.
You want the rifling to have a VERY snug fit.
Huvius's accuracy is quite decent for a large bore.
Round balls in paper ctg. gave me the same accuracy as cloth patched balls.
Today, that moose stagger'r is my match rifle.(.69 cal.)