Dear OP. I have a 45-70 Marlin SBL. The rifle was purchased a year ago. It is a fine rifle, functions wonderful and is very slick and smooth and reliable. Because it is stainless and laminate it is certainly resistant to weather. I like the FNC stainless GSBL version they have as well, might look for one. I do not need to do the Custom Shop route though because I can work my own weapons pretty good. I much prefer stainless steel whenever and wherever possible over blued. Both looks and function.
I was initially very attracted to the chrome Henry 45-70 but the quality control is not what I was expecting and I do not like the tube loading. A buddy of mine has one and it does not cycle reliably compared to my 1895 and it feels rough when I cycle it. And again, the tube loading and pointing a rifle at myself to load and unload is not for me. I can live with it in a rimfire but not in a centerfire. Too slow and cumbersome.