To make the dry rub, combine the brown sugar, seasoned salt, chili powder, pepper, cayenne, Old Bay, sage, and onion powder and blend well. Store in an airtight container in a cool, dark place until ready to use, for up to 6 months.
To make the barbecue sauce, combine the ketchup, sugars, vinegar, chili powder, dry mustard, Worcestershire sauce, salt, pepper, garlic powder, and celery seeds in a saucepan over medium heat, stirring to dissolve all the sugars. Heat, stirring occasionally, for 30 minutes. Cool to room temperature.
Set up your smoker to cook indirectly at 250 degrees F. Season the rib tips all over with the barbecue rub. Place on the smoker and barbecue for 4 to 5 hours, or until the ribs tear apart easily, basting with the sauce during the last 30 minutes of cooking.