I'd like to replace my tuners with some locking hipshots, but I'm not sure if I should get the 8.5mm or 10mm ones. I've read that Gretsch uses a non-standard hole size of around 8mm. Can any confirm that? I have a reamer, and I've reamed tuner holes before, so I'm not intimidated much by that. The finished headstock does give me pause though, because I don't want to crack my finish when reaming. Stuff I've reamed in the past is pretty much just sealed wood strat-style headstocks, and it's practically impossible to mess those up. Any tips on that (if I will need to ream the holes, anyway)? TIA for any help!