For the BBQ sauce: Mix the ketchup, vinegar, Dijon mustard, brown sugar, cayenne pepper, salt and black pepper in a bowl. Then transfer to a thick-bottomed saucepot over medium-low heat. Allow the sauce to warm, and mix over the heat for 10 to 15 minutes, stirring throughout the time. Then remove and cool until usage.
For the spice rub: In a bowl, mix the salt, ground mustard, paprika, black pepper, cayenne pepper, white pepper, seafood seasoning and cumin together with a spoon. After mixing, keep dry and covered.
To prep the ribs, remove the silver skin from the bottom side of the ribs. Then evenly rub each rack with 1/4 cup of the spice rub on top and bottom. Wrap each rack in plastic wrap and keep overnight in the refrigerator or cooler.
To smoke the ribs, heat a smoker with pecan or other fruit wood, bringing the smoker or pit to 165 degrees F and maintaining temperature. Once the temperature is obtained, remove the plastic and place the ribs in the smoker for 4 hours, keeping for doneness at this point. The ribs should be cooked, but not falling off the bone.
To glaze the ribs, remove them from the pit and glaze each rack with 1/2 cup of the BBQ sauce. Then return to the pit for 30 to 40 minutes. Again, remove and glaze with additional 1/2 cup sauce and finish for a final 20 minutes in the pit. After the second glaze and final cooking, remove the ribs from the pit. Allow to rest for 5 minutes, and then cut into single or double bone sections and serve.