I keep about 8-10,000 each of 9mm and 45ACP on hand, primed and ready to load. I made the effort to sort out 500 or so of each for load testng.
When I'm deciding between 2 finalist loads at 50 yds with a Ransom rest, the brass will be once-fired, one brand, +/- .001" long and +/- 0.2 grains in weight after priming. The bullets and powder charges get similar scrutiny. Handloading is a separate hobby unto itself.
When that fun exercise is over, and I've settled on the most accurate load at 50 yds (usually 3-4 MOA) I load up a few hundred in miscellaneous, unsorted brass. I've Ransom tested bulk loads enough time to know my sub- 2" 50yd groups are likely to double in size. I don't shoot formal bullseye; I just blaze away at paper and steel. I'll mark brass to be culled for various reasons (usually when crimping) but never weigh or measure it for general use.