So a friend of mine at work got hired on full time and to celerbrate we are doing an office pot luck. Well she asked if I would maybe smoke some meat for her. I feel pretty honored to be asked to cook but to smoke something wow LOL. We have roughly about 20 employee's that are going to eat and at least half of them are bringing in dishes. I figure cost and amount of food the best choice would be getting a Boston Pork Butt and making pulled pork. I have all my seasoning, and plans laid out. The only tiny problem I ran into was how big of a Butt I should purchase. Normally, I do amounts for family and friends which leads to some good leftovers for a day or 2. But to cook a butt to feed 20 people. I don't know how many lbs I'll need. Rule of thumb is 4 oz person from what I read but I think I'm the only person bringing in a meat dish. Also, we have an oven here at work. What is the best method to use the oven to reheat the pulled pork? Warm, 225, 250?