I've only done the split shoulders (usually about 4# per) myself. A friend did a whole shoulder on his split-log cooker, and it takes some TIME. Smoke and Spice says figure on 90 min per pound, but I've found their time estimates to be well on the low side. I usually pull the shoulder when it is way broken down and soft, 190? internal. So just half a shoulder takes me 10-12 hours. For a whole shoulder I would just say give it time, and keep the heat up around 230?-240?. Good luck!