I hate to be a wet blanket, and you've possibly already come to this conclusion... but...
Trying to be a "one powder" loader for the three cartridges you mentioned is probably going to be very difficult, if you want "good" results from all three.
I figured this would be the outcome - Basically I've gotten off to a good start getting closer and closer to the information I want. Since i'm working with a more outdated caliber on the 32-20 I'm hoping i can find something that will give me a middle ground on that one.
It's going to be a bit of trial and error (1 or 2 loads) with the slower powder at very low levels just to see if i'm on the right page. If no suitable solution can be found then I'll just wind up using the unique and being a two powder household.
I'm not planning on doing any hunting or anything with the 32-20, it's just a paper puncher for me(but maybe someday). Same with the 280 since it's semi-auto and can't be used for hunting here in PA. The 30-06 was purchased specifically for it's ability to be used for hunting but also to go to the range with.