I've had my Large BGE for right over a week and yesterday got a plate setter, but my ET-73 thermometer is still in the mail. Anyway I decided to go ahead and try my first Boston Butt since they had one five pounder left at Harry's.
I grabbed my crappy $4 probe thermometer that I've had for years and jammed it in trying to get in the middle away from the bone. I filled the egg with lump to right above the fire box, placed in some wood chips, and lit it with a starter block. I closed it up with the vents wide open. Once it reached ~250 I put in the plate setter and grid and closed it until it again reached 250. Next I opened it and put in my drip pan under the grid and butt sitting on the V-rack on the grid. Now I shut the lower vent to about an inch and put on the top with it shut and the daisy grid full open. As it approached 250 I started tuning the vents. It was now 9:30pm. My previous attempt at ribs was my low and slow practice so I had some idea of what I needed.
Initially it overshot to about 265, but I left it with a sliver open on both vents and it was a stable 250 by midnight. I woke up around 6:30 and it was at 260. A small daisy wheel tweak later left me at exactly 250 at 9:00am. At 10:00 I opened it to check the butt temperature and it was almost 185.
When would you pull it?