~z, this is a good question and I have my own theories about this tied into the OCW method. This is my thought process and procedure.
1. If the chamber/magazine combination allows, I start by seating all bullets 0.020" off the lands. If the magazine limits OAL then I seat the bullet for reliable feeding.
2. I want to find the CHARGE that produces the best results in terms of barrel harmonics as quickly as possible. In other words, a charge such that the average group center of three loads, OCW load - 0.3gr, OCW load and OCW load + 0.3gr is in the same place on the target (5-shot groups at 100 yards).
3. I generally want to maximize velocity so if the first OCW load is too slow, I push on to the next OCW load assuming that I'm not grossly exceeding published loads. I ALWAYS find the best results near the upper end of the load data so I don't waste time or money starting at the "starting" loads. I usually work up six or seven loads starting at 0.6gr over a published max and work my way backwards shooting the lightest load first and checking for signs of overpressure.
4. Once I find the OCW load with the required velocity, I realize that seating the bullet in or out won't change the OCW load ... it may affect group size a little and result in the groups moving up/down slightly due to slight changes in velocity, but whichever seating depth works best, that load +/- 0.3gr will group on the same place on the target which makes it the OCW load
5. I make up six sets of OCW loads (5 rounds each) with the bullet seated 0.005", 0.010" 0.015", 0.020", 0.025" and 0.030" off the lands.
After shooting these loads I know all I need to know. Using this method, five and six shot groups will be around 0.3 MOA at 100 yards, 0.5 MOA at 200 and 300 yards, 0.7 MOA at 400 and 500 yards and 1.0 MOA at 600 yards. Those numbers are due to my skill level and the wind and not the load. With no wind, I feel confident that 0.5 MOA is possible at 600 yards and maybe better than that. Just over a week ago I shot a 1.15 MOA 23-shot group at 600 yards with a variable 3 - 8mph crosswind. With my load, a 2mph difference in the wind means a 6" POA/POI difference at 600 yards ... almost 1 MOA so I know that a number of shots were blown off center that day.
I can usually find the BEST load (for a given powder/bullet combination) for any of my rifles in less than 100 rounds and usually a lot sooner than that (70 usually).