Place rings of onions in the bottom of a 6 quart or larger slow cooker.
In a small mixing bowl, combine together the ingredients of the rub (brown sugar, garlic powder & seasoning salt).
Rub each rib with the dry rub mixture and place in slow cooker on top of the onions.
In another small mixing bowl, combine together the Country Bob's sauce and BBQ sauce and pour all over the ribs. Gently toss with a pair of tongs to coat each rib in the sauce.
Cover and cook on LOW for 7 to 8 hours or until the meat is tender and juicy.