The S. Carolina Style butt I did was mostly at 225f, eventually because rain mighta kicked off, I bumped it up to 250f. That was..a 9 pounder? Not quite sure, forgot to record that bit, but I figure on 20ish hours any time I use my smoker for pork butt. My method is light a full tray of pellets at midnight, go to bed. Even if they burn quick, thats at least 6 hours. Then you can reload the tray..or just feed chips. As long as the heat is on, the food will be safe, so don't panic over the food safety bit.
The first use of my MES 140s I had two meat loaves an 8.3 pound pork butt in, some chuck roast...eggs..Chicken breast, think a whole chicken. That pork butt took the last time, only 14 hours, and I don't think I -ever- raised the temp over 240f. My Kalua pork butt experiment was a smaller one, and I unwrapped it from the banana leaves at 15 hours because it was still only 175-178. <Though it was wrapped in banana leaves>.
Suffice to say, I have determined if people actually plan for me to do pulled pork from my smoker, I'll likely start it 2 days in advance Lol.