I always set my fine tuners to their mid-position, tune up, then clamp at the nut. You never know if you'll need to fine-tune down or up, so I find mid-way is best.
Those clamping nuts really need a string bar to pull the strings down onto the headstock side of the nut. Only a few $ but they make a big difference to the locking nut's performance. You can then tune up on the main tuners without the clamping action affecting the tuning at all. It also means that the clamps are only holding the string in place, they aren't also trying to bring the strings down onto the face of the locking nut.
https://hazeguitars.com/blog/locking...bar-adjustment