If you were fitted with the MoRich wiki, you're going to have problems. Most of it is ok, but the pitch/angle philosophy horrifies me. It would work if we bowled in zero gravity, but with the forces exerted on your arm and hand during release, those pitch combinations don't work. If your thumb swells and shrinks that much, you have several problems with your fit which I'm fairly certain causes you to grip. I never used to swell that much, but I'd have tape come out at the beginning of the set, and then go back in a game later. Now I don't adjust at all because I got my fit dialed in. You've got some stress or force that's causing pressure, excess friction, or suction, so either you're gripping too tight, have a bad fit, or both, and I'm guessing both.