Re: If I ever meet the SOB....
I just got done doing 800 Winnie 308s and 500 RP 223s for friends. Even using my TrimMate, I still got two blisters doing the various case prep steps. After the second, I started drapping a bandaid over my thumb tip, with the cushioned pad placed over the pad on my thumb.
No problems after that and you still retain the tactile feel needed for snatching the cases out of the cup or dish.
Chris