Theoretically, Smoking alone may work but it would take a Long time for the heat in a smoker to break down the huge amount of Collagen, Cartilage and other Connective Tissue in Ox Tails to get them Fall Off the BoneTender. I am not sure it will even work and worst case you end up with Ox Tail Jerky! I would go with 4 hours of Smoke at 225*F then add them to a Dutch Oven or Crock Pot with 4C Beef Broth, 1 Lrg sliced Onion, browned, 1C Chopped Scallions, 1/2C Soy Sauce, 1T Fresh Thyme (1tsp Dry), 1-2 Bay Leaves, 1tsp Crush Allspice Berries, 1T Worcestershire Sauce, Fresh or Dry Hot Chiles ( 1whole uncut Habanero does nicely ) to taste and some S & P. Cover the whole deal and Braise in a 300-325*F oven, High on the Crock Pot, until all is Super Tender, maybe another 2 hours...Serve with Coconut Rice and Peas...YUM!!!...JJ