I have locking tuners on my electric guitar (a PRS); not Sperzels, but a newer variation that is less cumbersome and lighter. But I don't think they'll solve your "detuning" problem. If certain strings go up in pitch when you drop the tunings on others, the cause is probably not slippage through the tuners, but rather the neck reacting to the sudden decrease in tension by pulling back a little. It's the same thing that will happen if you gently pull backwards on the peghead; all the strings will go slightly sharp. It usually isn't all that dramatic if you only detune one string, but if the tuning does shift a little the solution is just to do some quick compensatory fine-tuning. If your existing tuners are in good shape, there's no need to replace them. If they're worn, I'd just replace them with good quality non-locking tuners -- Shaller, Grover, Gotoh and Waverly are all good brands.