I can only add that Jon is right about the locking nuts. My experience is that if you do have a locking nut then the locking tuners are not necessary.

Further, and this is just my opinion, but having played a boat-load of guitars with and without locking tuners, if you are properly stringing your guitar then you don't really need locking tuners unless you are using a whammy bar a lot with a traditional nut. But even then, you still have the problem of nut friction.

Any good tuners will work fine if you install your strings properly. And Sperzels weigh a lot relatively speaking, increasing the mass of the headstock. I could tell a difference on my Strat when I put them on.
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