All three cans are now in place and resting on the angle brackets.  You can see the 10 major
primary air holes in the burn pot's bottom as well as the curled bottoms of the 10 secondary air
supply holes in the 28 oz can.  This rests directly on the burn pot.  I believe this allows sufficient
secondary air into the wood gases, but prevents too much secondary air from cooling the
gases as they rise towards the cooking surface.  This is sort of the Goldilocks of secondary air,
not to much, not too little, just the 'right' amount -- and no more.