Good question. I get the bone in butts and they average 8 to 10 lbs in the Army commissary. I have never weighed the finished product but guessing a loss of 1 lb or so from the cook, 1/2 lb per person, assuming you have a variety of side dishes, should be plenty. We use regular, not BBQ, sized buns for the sandwiches. That helps stretch out the meat. Slider buns stretch it out even further.