Tim has a good point. The low thread count usually spread when seating the ball into the muzzle, which promotes gas cutting. The higher thread counts actually allow a slightly thinner cloth to be used. I've found a few that worked, drill, jean pocket material, that sort of stuff, but never buy enough to shoot a long time and when I go back to the yard goods store, it's out of stock. This is why I use .020" or .022" denim most of the time. It's easy to find, holds up great and works with about all ball sizes, .010" to .005" under bore size in normal .010" or .012" deep rifling.
: Taylor and I went out testing yesterday, shooting off some blocks of wood. I used a short 'round' of spruce firewood with a rabbit ear bag (short ears) underneath the forend while Taylor used a bunch of 2x6 boards with a bag of sand to get the right height. After all the shooting was over, we went out and picked up patches to check them. There were all reusable, as normal - no cutting, or scorching. He was using a .495" ball in his deep grooved Rice .50, while I used .395" as well as .400" balls in my .40 Goodoien barrel. We were using the same patch material and both started off using LHV lube. Taylor continued to use that lube, while I finished off testing spit.