Once I select a powder to use I always try and find the optimum charge range where minor deviations in powder charge weight have mimimal to zero impact on point of impact. I try and key in on a charge weight that lets me use my Lee Dipper Cups instead of an adjustable powder measure (I find it faster and easier). I do this using COL data from the loading manuals. Then I tweak my seating depth. Once I find the seating depth I make a dummy round that I use to adjust the seat die between loading sessions.
It doesn't always work cleanly because if you start with a bullet your gun just doesn't like you burned a bunch of components. But, when it does work, it is very repeatable over long periods of time. As an example, I couldn't get 55 grain bullets to shoot worth a darn in my 223 no matter what powder charge I was using. Switched to 40 and 63 grain bullets and all was good. I burned through a bit of powder and primers before I found the better (for my