Using a kitchen towel, grasp a corner of the membrane on the underside of each rack and pull off the membrane. If necessary, cut the racks so that they will fit on your grill. Sprinkle the racks all over with the Paprika-Ancho Spice Rub and gently massage it into the meat. Let the racks stand at room temperature for 1 hour.
Meanwhile, light a charcoal fire in a starter chimney. Add the lit coals to a grill and set it up for indirect grilling: Carefully push the hot coals to one side and place a drip pan on the opposite side and fill it with water. Alternatively, add the lit coals to the firebox of a smoker. Scatter half of the soaked hardwood chips over the coals.
Arrange the ribs on the grill over the drip pan. Cover the grill and cook for about 4 hours, maintaining a temperature of 225° to 250°, turning and rotating the ribs occasionally, until the rib racks are tender. Monitor the grill throughout the smoking process and add more lit coals, soaked hardwood chips and water to the drip pan as needed to maintain the temperature and smoke level. Cut the racks into ribs and serve.