T-shirts make lousy patches. For best results use tight cotton twill sold for the purpose, or pillow ticking that’s been well-washed to remove the sizing. Problem with pillow ticking is unknown thickness. You can measure at the store, but after washing, who knows?
The patch is the key link between barrel and ball. If you want good, consistent results, don’t scrimp on them. While no doubt fun, 6” groups are just awful.
