Hello all. After a few years of lurking here, I'm finally partway through an RF build. It looks a bit like a Lang patio, which I found on their site weighs in at something like 640 pounds! So now I'm starting to find ways to cut that down a bit....can I do it with the stack? I have a 48" piece of 1/4" round carbon (4" id), but I also have access to much lighter SS roughly the same diameter. So, the question is, are we still trying to heat mass by the time we get to the chimney, or will a lighter gauge stack be acceptable? Thanks in advance.