15# trimmed to about 13.5#, bought at Costco and the whole 15# would have fit. I may have trimmed too much fat off but the supervision here approved of the final product. 250F for 6.5 hours in Florida humidity - it was cloudy and light rain - cooked to 203-295F. it was very good but a leaner...
I cooked just for my wife and myself. We got a butterball 4.75# turkey breast at Publix. Had some misgivings with using a BB cut, but it turned out very good. Left the skin on, rinsed and patted dry the breast and used a buttermilk/salt brine for about 36 hours, turning the bag over 10-12...
Find the AUG setting and reduce to lower setting - I had the same problem and changed the AUG value to 10 and now the grill holds at 180'ish on the breezy back porch. You will need to remember to switch the AUG to 65 (default) or other higher value to maintain higher temperatures, say >250F...