Get your grill sizzling hot, put your dry rub on, throw the rack on the heat for just long enough to get some good grill marks (a couple minutes), then immediately sauce, and transfer to foil. Wrap it very tightly, and put in the oven at about 270 for 3-4, maybe even 5 hours. After which, poke it with a thermometer to not only check temperature, but get a feel for tenderness. The longer\slower you cook it, the more tender it'll be. It'll take a couple tries to get it right, but they're fall off the bone tender, impossibly juicy, and swimming in grill flavor.