One problem though, the locking mechanisms at the bottom of the hole are plastic, and I've heard a LOT of people say that it breaks quite frequently. So you either have to replace the outside "slug" or the transferable one, and if it's the latter, that means you have to drill a new thumbhole. Also, once you drill the first ball, every ball after that has to have the thumbhole EXACTLY the same depth, because if the lock is further down in the hole, or higher up, the transferable slug with either be dropped or raised, and naturally you can't have that. In theory, it's a good idea, but in reality, the risk just isn't worth it. It's easier and a LOT cheaper to just replace the slug in a ball that doesn't fit.
Hey, I am NOT Michael Jackson. I like little GIRLS, not little boys . .
Rock on kitty.