I have actually done 4, on three different occassions. I normally buy my butts from Sams in 2-packs. It seems total weight was around 30 pounds. I even crowd them on the bottom rack. Granted, it's probably not the best idea, but to be honest I haven't noticed any issues. I usually put my thermometer in the smallest butt and double wrap it in foil when it's 190 degrees and let it rest in a cooler and then temp the bigger ones making sure they get to 190 before removing the same way. It probobly takes a little mote attention to the grill during the cook. I just ordered a TTT and am looking forward to seeing how it works. Maybe I'll get some decent sleep next time.☺