In a small bowl combine brown sugar, seasoned salt, and chili powder. Brush ribs with mustard. Sprinkle brown sugar mixture onto ribs. Cover and refrigerate for 6 to 24 hours.
At least 1 hour before grilling, soak wood chips in enough water to cover. Drain.
In a grill with a cover arrange preheated coals around a drip pan. Test for medium heat above the pan. Sprinkle some of the drained wood chips over the coals. Pour 1 inch of water into the drip pan. Place ribs, meaty side up, on grill rack over drip pan but not over coals, or use a rib rack placed over the drip pan. Cover and grill for 1-1/4 to 1-1/2 hours or until ribs are tender, adding more coals and wood chips as necessary.
Brush with the 1/4 cup barbecue sauce. Grill ribs for 5 minutes more. Serve with additional bottled barbecue sauce. Makes 6 servings.