In .45-70 I've tried various alloys, and found both 15-1 and 20-1 lead-tin seem to work the best in mine.
I've also noticed that some people have gotten pretty good results in using much harder alloys. I've got some Lee 500-grain that I cast out of mongrel alloy; I need to load a few of them with a load that works well with 15-1 and see what they do. I know they probably won't shoot as well, but it's worth trying just to compare results.
Why no, I can't leave some things alone.