I get 82-84% attenuation with 1056 pretty consistently. I only use it for PAs and IPAs. I was huge fan of 1272 for a few years then it became harder to get so I went back to 1056 and haven't really been able to tell a difference. Both are great yeasts.
I've noticed attenuation rises a little in second and successive generations but not a lot. I've run 1056 for 6-7 generations many times and would go further but something usually happens to make me start over.