Hey Guys, I'm in the process of building the first of several smoker / grill combos. Thus one is an experiment because when I started I only had 8 hours of welding experience that I reciever 20yrs ago..lol, so bare with me. Pictured below is what I've done so far. Steel used is new 10 gauge plate, dimensions are 36W x 30H x 18D. It will be charcoal, wood with propane assist. The lower plate is 3/16 mild steel for the defuser plate. I intend to cut 2"w x 10" slots on the left and right side of the defuser plate with sliding plates to help regulate heat , havent decided if I will do the same width wise in the back of the smoker. My thinking for the slots is to help circulate heat when cooking a full load as well as help reduce heat loss on the sides and back if needed in cold weather. Haven't decided if I will insulate it because I already have enough 3/16 plate to build a 24wX24X72H Vertical. The center of the defuser plate will be cut for a stainless water pan, below the water pan will be the charcoal/wood basket made form #9 expanded metal with a 1/8 plate running across the middle to keep ash out of the black pipe burner that I am making following instructions from a link I found in another thread on this forum. Below that an ash pan. The upper chamber and lower will have its own set of doors.. I do have one question though, the cook chamber above the defuser plate is 21 inches. How far above the defuser plate should I place my first rack?