I have already determined that some bullets like to be seated out further than others.
I have over 6,000 rounds through 6.5mm Creedmoors with about 10 different bullets, all measured and documented so I have a pretty good database of what works for my rifles and powder-bullet combinations.

I do begin choosing the charge for each powder-bullet combination based upon the bullet's 'preferred' seating depth. Based upon the trim length variations, I make the adjustment around that depth by making slight adjustments in seating depth.
The seating depth adjustment rarely is more than 0.008 to 0.010 to tune to the precise exit time once I have chosen the powder charge to get within the exit time range for the preferred seating depth. Most times it is only a few thousandths.

When I started testing the theory several years ago, I would set up a set of loads with their exit times 0.005 msec. apart so I could document the difference in group size average.
As you already know, a 0.1 grain change in powder charge causes about 0.005 to 0.006 msec. in exit time depending upon the powder, so it was a convenient method of creating loads.
Turns out that the increments were pretty small and my shooter variations often masked the differences at those tiny increments.
I quickly concluded that the differences in exit times really showed obvious results when they were 0.020 msec. or more off the exit time goal and the biggest differences were apparent when the shock wave got closer to the muzzle.