Brine:

In a medium saucepan, combine about 2/3 pan of water, salt and brown sugar, then heat until liquefied, about 5 minutes. Place the ribs in a large aluminum foil roasting pan. Cut between the bones of each serving, 5-6 inches, to allow brine to permeate. Combine in the same saucepan 1 bottle of barbecue sauce and 3/4 cups ketchup. Optional diet cola can be added later, if desired. Pour the brine over the ribs and cover with enough water or cola and move ribs around to mix brine well. Keep cold for 2-3 hours. Measure enough heavy duty wide foil to about 2 1/2 times the length of a large baking sheet. Line the pan with about 1/2 the foil and leave the remaining half over the edge ready to fold over to envelope the ribs. Add about 2/3 cup of water and place ribs on top as evenly as possible. Season to taste. Chop the onion and place over top of ribs. Preheat oven or gas grill to 450 degrees. In a suitable bowl, combine remaining bottle of barbecue sauce, 3/4 cups ketchup, tomato paste, optional Liquid Smoke and hot sauce with flour and whisk together well. Pour sauce evenly over ribs, it should be thick. Fold remaining foil over ribs to form a bubble and press edges around the three sides to form a tight seal. Place in oven or in covered gas grill and cook for 1 1/2 hours. Carefully tear top of foil to pierce meat to check for tenderness. Be very careful to peel back foil and allow to brown for another 15-20 minutes as desired.