I have, and have a smith who does the work, a GB model takedown in 22, 303, 375 2 1/2", 45-70, 50-90, and 12 bore rifle. The GB has a large shank, so that could be a consideration for your action. 30-40 would work as well. I think the 50-90 is the most used in my set, but there is no need for a larger case unless you shoot black- I need a filler in the 50-90 as it is!
Doug