I am starting to work on a small patio size RF smoker. Picked up a couple air tanks for the cook chamber and fire box. Right now i am working on the design. I have a few questions before i get cutting. I'm new to smokers and i like to over think things so i am going to have a lot of questions. #1. I measured the tanks and by my calculations the big tank is about 19 gallons and the small works out to little over 5 (not the 21 and 7 as advertised) How important is the 1/3 rule? what are the issues of having a fire box less then 1/3 the cook chamber? should i be looking for something a little bigger or look at giving the fire box a little more capacity? #2. For the air inlet for the fire box is it better to be above or below grate level? Below seems like it would allow the fuel to burn better, but above I'm thinking it my have better control? Or have inlets both above and below? #3. Any point in having a damper of some sort between the fire box and cook chamber? #4, Am i over thinking all off of this?