I usually put my rub on the butt the evening before the smoke, wrapped in plastic wrap. I will smoke at 225-240F with hickory and try to maintain the smoke until the meat has reached 140F. After that I let the smoke subside. I will spray the butt each hour with a 3-1 mix of apple juice and bourbon. When the temp gets to 165-170F I will double wrap in HD foil, add a bit of my spray mix to the packet and cook the butt up to 205F if I'm going to pull it. (170F will do if you are going to slice it) If I'm going to pull the pork, after it gets up to 205F I will wrap it in a couple old towels and let it rest in an insulated cooler for an hour or two. When you remove the towels and open the foil the bone will practically fall out.
Most of this cook is based on temperature. A 7-8 pound butt will take 8-10 hours to cook plus the rest time in the cooler. Give yourself plenty of time. Another thing to be aware of is that sometimes butts (and briskets too) will "plateau" or stay at the same temperature for an unseemly long time. Please don't be tempted to raise the heat, but rather wait it out. A digital probe thermo is a big help with this cook so you know what the internal temp of the meat is.
Some folks here will put a layer of yellow mustard on the butt before putting the rub on. A lot of this is personal preference.
Meowy's got it covered there! Pork loves mustard! I used powdered mustartd in my rub so I don't need the French's slather. I know it sounds weird but you won't taste it when it's cooked. It sort of helps make the crispy outer edge we know and love and holds in the juices.
Speaking of juices ... as Meaowy said apple juice it good for a spray and so is orange juice. The sugars in the juice tend to caramelize and brown up nicely.
Don't be surprized if you butt sits at say 130 - 150 for 2 to 4 hours! Hitting the plateau is sometimes very frustrating but man is it worth it!
I don't use a digital thermometer - tried it but it didn't like the cold weather so I went back to my trusty dial therometers. Msst people here will swear by them though - either will work.
The double wrap in aluminum foil to rest the meat is very important! It'll make the meat so tender and juicey you'll think you died and gone to heaven!
Just to add some photos, look at the thread I just did a few nights ago. I did shoulders, which is prepped the same as butt. Hope it comes out sweet!
I used two forks to pull the meat. First I put a few chucks on a cutting board next to a big bowl, sort of press on a chunk to see which way it's going to "string" then rake it with the other fork. You'll know what I mean when you do it. Good luck!
PS: Eastern NC finish, mop, or sauce, whichever you call it, is tangy and delicious. They all have various measures of cider vinegar, sugar (brown or white), crushed red pepper flakes (like for pizza), black pepper. Smaller more varietel areas use molassas, salt, chili powder, chili sauce, hot sauce, and W-sauce. As you move west in the Carolinas, they start using the fruit of the Devil, the tomato. As you go south into SC, they prefer a mustard based sauce. They're all dee-lish on pulled or chopped pork BBQ, just play with the ingredients until your family is happy, then record the recipe.
If you wait it out and take the time to get the internal temp of the butt above 200F and then let it rest at least an hour before opening the foil, you will be able to pull it with your hands. I usually wait a little longer so I don't handle really hot pork.
I toss a couple of fist sized chunks of pork butt into my KitchenAid mixer that had the paddle beater in place. Run it on power level three for about 20-30 seconds and it shredds just fine with out the "ooch ech ouch". I then dump the shredded pork into a hotel pan and start over. This is really great, especially if you have a bunch of butts to pull.