Nothing I have ever shot in 45s comes anywhere near case filling unless it was BP.
Generally use Red Dot, Nitro 100 or AA2. They can double or triple charge in a case.
Actually I a more worried with squib loads. Can also be a little sooty but thats why I have a tumbler.
Essentially the slower the powder the more you can put in the case, but you end up on the high end of the velocity range
You want to stay at 925 more or less. The most case filling will be trail boss.
The specific reason is not important, but I have started charging cases as a separate operation, sit the charged cases in a loading block and visually inspect to insure power is in each and there are no double or triple charges, I then seat the bullets.