To what degree of doneness are you looking for? Are you cooking it to be done as a roast beef, or to fully smoke it to either slice it or pull/shred it? For a roast beef like temp, I would pull it off at 145-150. To slice I would wrap it in foil at 165 then pull it at 190. To pull/shred I would wrap it in foil at 165, then pull it at 195. In both instances, let it rest for an hour, wrapped in a towel, in a dry cooler before either slicing or pulling/shredding.