I'm building a smoker to make Pulled Pork for our high school football games. I believe this design will support 750-lbs (15 racks supporting 50-lbs of shoulder each. The oven below will sit on a trailer. I've started welding the chamber. I need to enclose the oven. Since I have a rigid frame to attach the steel to, I was thinking 14 or 10 ga. steel would be sufficient... I see all sorts of smokers built of 3/16 to 1/4-inch steel, but these are all pipes, and are part of the structure itself. My Char-Broil that I've used for nearly 8 years is thin as can be, and works just fine. I'm going bigger... how much thicker do I need? Also: I was hoping the use gas burners to keep it to temperature after the initial smoke (after 8-hours, but supporting the remaining 8 hours or so). I've read the messages about gas inside the chamber and don't like it... so I've shown small burners under the "floor" of the cooking chamber... will these keep the inside at that wonderful 220 degrees? Any suggestions appreciated. Attached is the "design"