Season ribs with salt and pepper. Place ribs on a medium-hot grill over indirect heat; close grill hood and grill until ribs are tender, about 1 1/2 to 2 hours. (add more charcoal briquettes to fire, if necessary, to maintain grill temperature of about 325-350 degrees F.) Finish by turning and basting ribs with barbecue sauce for the last 15 minutes. Serve ribs directly from the grill or, for extra tender ribs remove from grill, wrap in heavy aluminum foil. Place foil-wrapped ribs in brown paper bags, close bags and let ribs rest for up to an hour. Unwrap ribs, cut into serving pieces and serve with extra barbecue sauce.