How big? Plan on 1.5-2 hours per pound. You can smoke it anywhere between 225-350 and it will taste great, it's real hard to mess up, I smoke around 230. I have stopped using the Texas crutch, it does speed up and get past the stall, but i think the bark is better if you don't wrap with foil, and you may get some delicious burnt ends, if it stalls for too long I just kick up the the temp a tad. Cook til 195, then wrap in foil and some towels, put in a cooler for a couple hours. You have four hours to safely serve after it gets below 140, so you should be able to keep it warm plenty long enough. I also have stopped injecting, it makes it take longer and a shoulder has plenty of fat to keep moist. My $0.02, I've got an 8lb Boston butt on right now smoking with Apple wood. Also have some jerky on there.