Mix together rub ingredients. Soak chips in water while allowing pork shoulder to come to room temperature. Grill over indirect medium heat for 5-6 hours: it should be tender but still juicy with an internal temperature of 180-190F. Add wood chips to smoker or tinfoil smoker roll halfway through cooking.
Bring sauce ingredients to a boil before reducing to a simmer for 10 minutes.
Chop pork or pull together with finger or two knives, removing burned or fatty bits. Mix meat and sauce and serve over toasted buns with mayonnaise.