The Schaller Mini Locking Tuners have the hole for the strings at a much lower profile than most conventional tuners, so the break angle is slightly increased. This is of help to straight headstocks such as strats.
We have soloist in the office with the abovementioned headstock style, which utilizes a straight string pull over the nut. It has a Original Floyd Rose trem and SML tuners, with a white corian nut.
It's had a pretty decent setup job done on it when one of the staff took it home for the weekend.
For the life of me, I cannot get it to go out of tune, even with the most Vai-ish wammy abuse, pressing it completely sharp to the point that it frets out and the saddle clamp bolts touch the floor of the recessed route, to the opposite extreme of dive-bombing to total string slack.
What does all of this prove?
Locking Tuners, in conjuction with a good bridge design, in conjunction with a straight string pull, in conjuction with a well performed setup job, will yield and instrument that will stay in tune, and do so consistently.
Hopefully that is of some help.