I think the Blowin Smoke reverse offset smoker is the same as the HBT Smoker which I’ve been cooking for a few years now.
The dampers on the firebox door obviously adjust the air entering the firebox. More air, more flames (heat) too little air and the wood will smolder creating dirty smoke.
I use my rib box/ warmer as a warmer only, I’ve never needed that cook space. Because of this I leave the damper from the cook chamber closed, since it sits on top of the fire box it stays plenty warm to keep anything warm while your waiting for your other food to finish . If you were going to use it for cooking I would open the damper going to the cook chamber and the damper at the top of the rib (exhaust). I would also shut down the chimney damper so your heat and smoke is being directed through the rib box.
Like I said I use my rib box as a warmer, when I first got the smoker I practiced with with using the rib box as a cook chamber and I remember it being pretty consistent or at least a consistent as any offset.
If you google cooking on a HBT smoker, there a few videos posted that explain things.
Hope this is helpful.