I bought a half a butt (a bit over 4 pounds) this morning and have it on my pit boss now.. Heres how I do it just for reference:
start the smoker preheating with lid up, when it starts smoking hard and you hear the fan kick on, and the smoke blows away, close your grill and dial up 225,
unwrap the butt and put it on a cookie sheet or whatever, I do not use any binder, no need imo, I season the fat cap with a kosher salt/coarse black pepper mix, the other 5 sides I use a lite sprinkle of Butt Rub, and a moderate sprinkle of Stubbs Rub.
Put the butt on the grill Fat Cap Down and close up for 1 hour,
turn the butt over to make fat cap up and close up for several hours maybe 3, I dont spritz my but with anything, I feel there is enough moisture in the fat that is constantly rendering.
when the butt reaches an internal temp of 165 or thereabouts, I wrap it in foil and put in a pan and put that in a 250 degree oven, you can keep it on the smoker if you like but your not getting any more smoke in the meat.
for estimating purposes, you should have to cook your butt an hour and a half for each pound, but if you dont have a meat thermometer, you're not serious about this and probably wont do any of this.. 203 internal temp is ideal, but the meat will continue to rise after you remove from heat to rest, so I remove at 198 and let rest for 1 hour,,
at this point, I shred the meat, all of it,, I dont pick out anything except the bone,, leave all the fat in .... this is crucial for good moist bbq,, I use a food grade 5 gallon bucket with a clean/new paint mixer in a battery drill, I have found that this distributes the fat and the meat better than anything else Ive tried, do not over mix,, you can turn it into mush, no good, just mix it up ..
I like to chop mine after this to get the best mouth feel and taste.