I was hoping to get some advice for my propane tank build. I'm all set on doors and hinges and calculations but my father in law who is going to help me put the firebox together INSISTS I don't need anything thicker than 14 gauge. I don't plan on going any less than 1/4" I just wanted some reassurance from you all. Also, on the smokestack, does thickness matter as much? I figure since that's where all the heat and smoke escapes, I might be able to get away with something thinner than 1/4". I have a virtually unlimited supply of 16 gauge.