At 225 to 250, you can figure 2 hours per pound. May go a little over with a long stall during a start to finish naked smoke. You can save time by taking it to 160 , 4-5 hours of smoke, foiling and finishing in the oven at 300. If done early, foil, towel and a cooler will hold the meat hot 4-5 hours. Butts stay moist all by themselves, no spritzing needed unless to smoke hot and fast. Spritzing adds 20-30 minutes to the cook each time you do it because of evaporative cooling and opening the door, releasing heat...JJ