I am in the process of laying out the build for the install of my 30NC. I have done some searching on the forum and found a couple of posts that are helpful. My plan is that I would use steel studs and 2 or 3 layers of Next Gen Durock to get to my 1.5 R-value. Is this the preferred way or is there a better way? Height of the hearth is not an issue as i plan on lifting it up around 10"-12" from the floor. Does anyone have any suggestions on my proposed setup?