std7mag, I have always done it this way, wrong or right, the first time I try a bullet/powder combo, I check the load data and pick a range of powder charges, then load up 3 of each and shoot, .5 gr increments through a chrono at 100 yds to see which charge weight gives me the best groups, especially if a string of them is good, I call it OCW or looking for optimal charge weight. When I pick a few of the best, I load them again and shoot about 7 each at 200 or 300 yds again.
Whichever charge weight shows the best groups, Then I start doing Coal tests starting about .020 off lands to find the best COAL, and then I call that my best load for that combo, one powder charge weight, one COAL. I also know I have to adjust later for barrel throat erosion.