Place another two layers of foil on top of the rack. Pinch foil together all around the sides to create a package. Repeat with the other rack of ribs, dry rub and foil. Place both baking sheets of ribs into the preheated oven. Bake for 3 1/2 to 4 hours, or until ribs are falling-apart tender. Open up the rib packages, gently transfer the ribs to a cutting board and cut into one or two-rib chunks. Drizzle with barbecue sauce.