Re: Schaller locking tuners?
Some of the locking models now have a mechanism where there is no thumb screw to tighten. My Grovers are like that....you twist the post until it clicks into place and the holes line up. Insert the string and turn the post and the "inner post" turns until it locks on the string, and then the whole post turns as normal. Retains the stock look.
I also had the Fender/Shaller locking tuners on my USA strat and liked them a lot as well. Haven't tried the Sperzels, but they have a good rep as well.
My biggest criteria isn't brand, it's matching as closely as possible the stock look of the guitar. Grovers would probably be the closest on your SG or Schecter.