Thats a little smaller than I want to do. I have done the same with my smoking box in my gas smoker. Just uses too much fuel.
EDIT: This does point out one thing to me. Charcoal is produced by heating wood to a high temperature in the absence of Oxegyn. Like wood wrapped in foil, placed in a smoke box, or in a closed 30 gallon drum. Each of these methods produce charcoal because this is little or limited Oxegyn. Where the method I proposed, in a starter chimney, would provide all the Oxegyn needed by the wood to burn up leaving only ash and wood that has not been burnt yet but no charcoal. So what I need is something like the closed 30 gallon drum loaded with wood chunks inside the 50 gallon chimney with a fire raging fire going though it. At least now I have a good idea if what I want.
Char Griller Akorn Kamado
Auber Industries PID Controller (SYL-1614SYS)
Everyone likes a little butt, but no one likes a smart butt.