1. Mix all spicy chili rub ingredients in small bowl, set aside.
2. If using a fresh ham or picnic roast, remove skin (see illustration below). Massage dry rub into meat. Wrap tightly in double layer of plastic wrap; refrigerate for at least 3 hours. (For strong flavor, the roast can be refrigerated for up to 3 days.)
3. At least 1 hour prior to cooking, remove roast from refrigerator, unwrap, and let it come to room temperature. Soak 4 cups wood chips in cold water to cover for 30 minutes and drain. Place the wood chips in a small disposable aluminum pan.
4. Place the wood-chip pan on the primary burner (the burner that will remain on during cooking, see illustration below). Ignite the grill, turn all the burners to high, cover, and heat until very hot and the chips are smoking heavily, about 20 minutes. (If the chips ignite, use a water-filled squirt bottle to extinguish them.) Turn the primary burner down to medium and turn off the other burner(s). Set the unwrapped roast in the disposable pan, position the pan over the cooler part of the grill, and close the lid. Barbecue for 3 hours. (The temperature inside the grill should be a constant 275 degrees; adjust the lit burner as necessary.)
5. Adjust oven rack to middle position and preheat oven to 325 degrees. Place roast in pan and wrap with heavy-duty foil to cover completely. Place pan in oven and cook until meat is fork-tender, about 2 hours.
6. Slide the foil-wrapped pan with the roast into a brown paper bag. Crimp top shut; rest roast 1 hour. Transfer roast to cutting board and unwrap. When cool enough to handle, "pull" pork by separating roast into muscle sections (see illustration, below), removing fat, if desired, and tearing meat into thin shreds with fingers. Place shredded meat in large bowl ; toss with 1 cup barbecue sauce, adding more to taste. Serve with remaining sauce passed separately.
STEP BY STEP: Key Steps to Pulled Pork
1. If using a fresh ham or pinic roast, cut through the skin with the tip of a chef's knife. Slide the blade just under the skin and work around to loosen it while pulling it off with your other hand. Boston butt, or shoulder roast, does not need to be trimmed.
2. Set the unwrapped roast, which has been placed in a disposable aluminum pan barely larger than the meat itself, on the cooking grate opposite the coals and the wood.
3. After cooking, as soon as the meat is cool enough to handle, remove the meat from the bones and separate the major muscle sections with your hands.
4. Remove as much fat as desired and tear the meat into thin shreds.
STEP BY STEP: Using a Gas Grill for Indirect Cooking
Remove part or all of the cooking grate. Place a foil tray with soaked wood chips on top of the primary burner. Make sure the tray is resting securely on the burner. Replace the cooking grate. Light all the burners and cover the grill. When you see a lot of smoke (20 minutes), turn off the burner(s) without chips and place the food over it. If the chips start to flame, douse with water from a squirt bottle. Cover the grill.