Hello, I am looking to get some feedback to install the hearth on my Lopi 380t. Ul listing say is that it just has to be 3/8” minimum thickness of fireproof millboard. My plan is a sheet of 16g sheet metal, durock, then slate tile. All screws staying on the outside of the of hearth. This would exceed the thickness. Just wanted some feedback if this is sufficient or I’m missing something.