In many discussions about this, it's a chicken or egg first type of debate.
I personally use a moderate pressure load to both fireform new brass and find a best seating depth at the same time.
Doing this up front makes ladder testing results way easier to decipher.
Use of a milder load enables me to go into lands without spiking pressure so much as to interfere with what I'm doing.
Several times I've gone back to tweeking(aka fine tuning) with seating, but so far this has not led to better results, or anything even close to 'fine tuning'.
There is another camp that decides to jam, or even soft seat, right up front & leave it there. But I declare that this is a terrible approach with hunting capacity cartridges, as best seating(most accurate) truly could be anywhere. This is what Berger demonstrated very well.
For many years it has been assumed in stone that VLDs must be jammed...
THIS WAS NEVER TRUE.