Given the unpredictable nature of cook time for pork butt what time of day is usually best to start things off? Early morning and hope its done by dusk or afternoon and hope it doesnt get over cooked overnight. I have not done any mods to my smoker yet so I am very timid about letting it run overnight
If you don't want to run overnight, I would smoke the day before and then reheat it in a crockpot with a bit of Apple Juice. Pulled pork is very forgiving and reheats really well. I'm sure those with more experience than me will chime in shortly.
I just did a 8 pounder. Started at 9 pm Friday. Done at 12:30 PM Saturday. IT 190F. pulled then reheated for Sunday.
Pork butt generally takes about 1.5 hours/pound at 225oF to reach an internal temperature of 200o (for pulling). The key word is "about," since it can take much less or much more (over 2 hours/pound). When it's done you want to FTC (wrap in Foil, again in Towel, and set in Cooler) for 1-3 hours to redistribute the juices and rest the meat before pulling. It's ready when it's ready so, as rcger says, do it the day before and reheat with some juice or drippings - it's as good or better that way and it's ready to serve when you are. Many of us smoke more than we need and freeze for later use - it's a good habit to get into (I usually do 2-3 butts at a time and freeze in 2-pound packages).