Whisk together the first eleven ingredients, through to the chili powder, to make a rub, breaking up any clumps that form; set aside.
Pat the ribs dry with paper towels and place on a cutting board. To remove the thin membrane attached to the underside of the ribs, first flip the ribs over so they’re bone-side up. Starting at the end of 1 rack, slide the tip of a paring knife between the membrane and the bone, then lift and cut through the membrane. Grasping the membrane with a paper towel, pull it toward the other end of the rack and completely remove it. Repeat with the remaining 2 racks. Rub the ribs all over with the mustard (about 3 tablespoons per rack), then evenly sprinkle with the rub mix. Place the ribs on a baking sheet, covered with plastic wrap, and refrigerate for at least 30 minutes. Meanwhile, soak the wood chips in a bucket of water for at least 15 minutes.
Set up your smoker to hold a temperature around 250 degrees F for about 6 hours; remove the cooking grate and set it aside. Fill a chimney starter three-quarters of the way with charcoal, then pour the unlit charcoal onto one side of the charcoal grate. Using tongs, stack the charcoal in a slight slope against the side of the grill bowl. Remove 1 cup of the wood chips from the water, shaking off any excess water, and lay them in the middle of the unlit charcoal. Fill the chimney again halfway with charcoal. Place the chimney on the charcoal grate next to the unlit coals. Lightly crumple three to four sheets of newspaper and place them under and inside the chimney. Light the newspaper through the holes at the bottom of the chimney. After about 5 minutes, the charcoal should be red and flames should appear at the top of the chimney.
Carefully pour the lit charcoal onto the pile of unlit charcoal on the grate. Use tongs to stack the lit coals on the pile. Top the lit charcoal with another cup of drained, damp wood chips (you should have 1 more cup of wood chips left for regulating the smoke as the ribs cook). Set the empty chimney aside. Place the 8-inch square aluminum pan next to the hot charcoal (this is the drip pan). Set the cooking grate back on the grill. Set an oven thermometer in one of the grill lid’s vent holes or on the cooking grate near the edge of the grill and opposite the charcoal. Cover the grill, making sure that the bottom and top vents are open and that smoke is coming out of the vents. (If smoke is not coming out, check your fire to make sure it is lit. If it’s not, relight it, using tongs to transfer the warm charcoal from the grill back into the chimney starter.) Let the grill heat until it reaches at least 250 degrees F, about 15 minutes.
Place the ribs on the cooking grate bone side down, but not over the flaming charcoal. If all three rib racks do not fit, cut one rib rack in half and wedge it against the side, making sure it does not sit over the lit charcoal. Cook, covered, making sure the lid’s vent is over the ribs (not the fire), for 30 minutes. Flip the ribs over and rotate their positions. Check the grill temperature: It should be between 250°F and 350°F. If it’s too hot, close the lower vent by half. If the temperature is too low, make sure the bottom and top vents are open, or you may need to feed your charcoal by lighting more in the chimney. Cover and cook for another 30 minutes.
Continue to check the smoker while the ribs are still cooking. Around the three hour-mark, wrap ribs tightly in aluminum foil to form an airtight seal. Return them to the smoker, bone side up, and smoke for 2 additional hours. Unwrap ribs and return to smoker, bone side down, for 1 more hour.
Check for doneness by lifting up one end of a rib rack. The rack should bend slightly in the middle. (The meat should not fall off the bone. It should be pink in the center with smoke lines running around the cut areas.) If it does not bend, continue to cook, covered, until it does.
Once you've removed them from the grill, let them sit for 10-15 minutes. Then slice into desired portions and serve.