Boss man asked me to do a few Boston Butts to feed folks at a kayak fishing seminar on Saturday. I have cooked plenty of boston butts on the egg before but Ive never done two at a time. I cook at 250 for about 2 hours a pound normally. I have two bone in butts at around 7.5lbs each and need a little help for the time. Should I allow more time and cook for a total of 15lbs or will they cook individually in the same or close to time?