I have recently began using Ron-c's Majic carpet. OMG what a difference it has made. I no longer knuckle the ball.
When i got my new ball, i had the problem with the rough/sharp edge. I had the pro guy file it down. But even still, i was getting caluses where my thumb connects to my hand. But, 2 games with the magic carpet and the calous is nearly gone. and definately no pain.
The magic carpet is loop pile carpet. It is actually angled down. for maximum holding power, you put he carpet in so the pile angles to the center of the ball, if you want lesser holding power you angle the loop to the outside of the ball. Oh ya, its supposed to go on the back of your thumbhole.
The pile is about 1/4 in thick, but is squisy, so if you have a little play in your thumbhole, you should be able to add the carpet without resizeing you hole.
I think it is wonderful. Its like $2 each with a minimum order of $20. So you get 10 for $20.
I can resist everything but temptation.
Storm Trifecta 15lb
Blue spare ball 15lb