Spritzing, Moping, spraying are all fine for a fire burner. Spareribs: I always used a simple butter, Apple cider vinegar, salt & Pepper warmed in a sauce pan to mop with. With Electric smoker I don't spritz, mop, or sauce and I use the 3 2 1 method for the most part. When foiled oddly I use squeeze butter, apple cider vinegar, salt and pepper. The bend test as stated above if the definitive method for testing doneness on a fire burner. With an electric after a 2 hour foil chances are good its going to break easily. You'll see a meat drawback exposing bone and cooked protein exiting the rib bones.
Beef ribs, are just salt and pepper, maybe a nice massage with Lea & Perins.
Spares by 3 2 1, obviously about 6 hours, usually. non-3 2 1 about 7 hours.
Beef ribs I use the toothpick test like with a brisket, looking for a 160/165 IT
Beef broth, butter, salt/pepper, Lea & Perins, Jacque Daniels or beer?
Vinegar is usually used because it help break down the collagen or connective tissues to make the meat tender. Oil/butter is for flavor and browning.
I use fruitie with my poultry but not normally with my meats.
Course these are just my observations, you need to figure out what you like. Then how to make that work for you.
Oh and if you are using electric, moping spritzing are really not needed.
Hope ya have full and enjoy the smoke.