I've done 4 racks of Stl spares in a rack in a kettle, coals banked to one side. It was a tight fit bacause the coals took too much space. I think having two banks of coals and keeping the rack in the center would work great. That's my plan for next time. Temps stayed around 275F the whole cook (measured at the vent) but it cooked more like at 225F on my WSM. I like higher heat spare cooks so will probably shoot for 325F next time too. HTH