John, two pieces of advice based on my experience and opinion.
1) For pork butts, 225 takes forever. 235 - 250 produces same results and shaves hours off your smoke time.
2) Go up to 8 oz. of wood and make the added weight in hickory. Smoke will never reach the center of the shoulder but pulled pork gets its flavor from blending the stronger flavored bark with the inner meat.