About one hour before you plan to start grilling, make the rub: In a small bowl, combine the brown sugar, salt, chili powder and pepper. Place ribs flat in a roasting pan.
Brush mustard in thin layer all over ribs. Sprinkle rub evenly over ribs and rub it in slightly. Set aside at room temperature for one hour.
Preheat the grill for indirect cooking at 250 to 300 degrees F. Add the drained wood chips, if using.
Place the ribs, meaty side down, over a drip pan, close the grill, and cook for 1 1/2 to 2 hours, adding about 12 coals to a charcoal grill every 45 minutes or so to maintain the heat.
Meanwhile, make the barbecue sauce: In a small saucepan over medium-low heat, combine the barbecue sauce and honey, and bring to a simmer, stirring often, to blend flavors. Set aside to cool.
Remove ribs from the grill. Double-wrap each rack in heavy-duty aluminum foil. Return wrapped ribs to the grill and cook until very tender (open packet to check), 1 1/2 to 2 hours more, adding more coals as needed to charcoal grill.
Remove ribs from grill. Being careful of hot juices, unwrap ribs. Return unwrapped ribs to grill and brush the ribs with the sauce and continue to cook for about 5 minutes, until the sauce is set. Turn ribs and repeat with more sauce. Remove from the grill and let stand for 5 minutes.
Cut the racks into 3- or 4-rib sections and serve. Serve immediately with the remaining sauce.
Serving suggestions: This foil-wrapped method yields moist and tender “falling-off-the-bone” meat. Accompany the ribs with roasted sweet potatoes, collard greens, and cornbread.