I am building this oven from the book and don't have the full plans.. which has required a lot of problem solving.. I think it looks pretty good.. be gentle if you make fun of my build .. haha .. In the book they talk about using a high silica cement in the arch for ovens in consistent use.. I'm in Japan.. so getting this sort of thing can be tricky .. anyway I already have 11cm of fire brick in the arch.. I have a lot of clay, so I could easily add a transition layer of that between the arch on the cladding.. I figure even 1.5 inch of clay plus the aluminum foil and the medium changes would put the cladding far enough out to keep it strong ... suggestions? Thanks!!