Let roast stand at room temperature for 1 hour. Preheat smoker to 275°. Add wood chips or pellets to smoker according to manufacturer’s directions., Trim excess fat from pork, leaving some exterior fat. Pat roast dry; rub with mustard and sprinkle with spice rub. Place pork in smoker. In a spray bottle, combine apple cider and vinegar; lightly spritz pork. Smoke, spritzing every hour, until pork reaches 165° and is a dark brown color, about 5 hours. , Transfer pork to a 13x9-in. baking pan or large cast iron skillet; liberally spritz with cider mixture. Cover tightly with foil and return to smoker. Cook until pork reaches desired degree of doneness. For slice pork, cook until pork reaches 190° to 195°, 2-3 hours longer. For pulled pork, cook until 200° to 205°. Remove and let stand at room temperature, covered, 45-60 minutes. For slices, cut around bone and cut roast into slices. For pulled pork, remove bone and shred pork. Skim fat from cooking juices; toss pork with cooking juices.