Mix rub ingredients. Make a double or triple batch if you like and store for a few months in a jar, or longer in the freezer.
If you want, remove the translucent membrane from the back of the ribs. This membrane won’t really tenderize during cooking, and can make for some chewy eating. It’s not difficult to remove, but it will take a little time. See how to here.
Use all the spice rub on the ribs, coating front and back.
At this point you can cook the ribs in the oven for a while, and finish with an hour or 2 of indirect heat on the grill, or give them a faster finish on the grill with soaked wood chips to impart the flavor of the grill. Or you can cook them a while on the grill and then finish them in the oven. If you cook them in the oven, be sure they are tightly wrapped and cook at 250°. The finished ribs will be very tender and shrinking away from the bone so that the bones stick out a little from the meat.
To cook on the grill, build the charcoal to allow indirect heat, or heat your gas grill for slow cooking. Put the ribs on your grill so that no meat is directly over the coals and close vents or turn the heat controls to keep the heat at around 250° or so. Four racks of spare ribs is too big for my little kettle grill. In the old days, I used to cook 2 racks slowly in the oven while I cooked the others on the grill, then they all changed places. Now I have a rib rack that holds the ribs vertically. Total cooking time should be 2 to 3 hours. Keeping the heat on the low side — as low as 180°, will extend the time but might allow you some flexibility.
If you like, spread on your favorite barbecue sauce either after the ribs are finished, or 10 minutes before the end of cooking.