Help installing a neck with a new nut. Chicken or the egg?

So I am installing a new bolt on neck . It is a brand new neck so no neck joint holes and no nut on the headstock.

to dill the holes for bolting the neck on I see a lot of guys put the high and low e strings on the guitar loosely and clamp the neck in place before drilling. They make sure the E strings line up correctly.

For the nut I see guys put the E strings on to get the correct location marke out on the nut.

But what if you have to do both? Which do you do first? Rough in the nut enough to hold the E's in place to get the neck position right? Let the strings slide around freely on the nut while you are trying to get the neck position right?

I figure I would probably try both but just wondering what an experience tech would do..

Thanks