Have your butcher crack each rib bone at the rib tip so that it will then be possible to separate the ribs without having to cut through bone. Trim excess fat. Rinse ribs. Dry. Sprinkle them with meat tenderizer, salt, pepper, and seasoned salt. Place the ribs in a deep pan and marinate them in Worcestershire sauce and teriyaki sauce for at least 12 hours but preferably overnight. Cut the slabs into thirds. Cook the ribs on a hot grill at about 350 degrees. The large ends of the slabs should be put on the pit first, the center-cut ribs five minutes later, and the short ends five minutes after that The ribs should cook 45 minutes to 1 hour.
Remove the ribs from the pit and separate them with a knife. Mop them with barbecue sauce and wrap them in heavy-duty foil until you axe ready to serve them.