Brian,
I have tried as hard as 12-1 in my .45-70, but for me it offered nothing over my 11 BHN (16-1) in that rifle. My .40-65 would probably shoot with anything from 20-1 up through 12-1 and never blink.
With my .44-77 I still don't know what it likes and I won't until I try something and it tells me it likes it or it doesn't. I have not tried anything but Kurt's 18-1 in this rifle so far. I think I need to try something harder. In my .45-90 when I first started paper patching and I was just starting to have some success but was still having a few fliers I tried 16-1 and things improved immediately in a big way. I used 16-1 for all of my paper patching until Kurt told me about the 18-1 alloy he was using. I have to say it works great in my .45-70 and because my .40-65 doesn't really care about alloy I use it in that one two.
A year ago I had Shiloh put a 17-twist Krieger barrel on an old rifle and chamber it for the .44-77 and because 18-1 was what I used in my other rifles that is what I have been using in this rifle as well. It shoots very well out to 300 yards and seems to not do so well beyond that. I need to figure out what needs adjustment and alloy is a possibility. If 16-1 improves things I will probably try some harder stuff eventually. I do expect to see an improvement with the 16-1.
I will be trying a few different things at Rapids next weekend and I'm sure one or more of those will show improvement over what I had 2 weeks ago. I'll review the result and adjust as needed and move on to the next match which is Lodi. There I am likely to try a thing or two different and then settle back for a long, long winter and think about things some more. I took on the .44-77 because I enjoy and need a challenge and I'm working my way through that challenge and having fun doing it. I never stop learning and I never stop improving things. It's a great sport!