You talking Beyoncé, Obama, Lohan, a standard butt can be 6 to 10 pounds.
Normally I figure a 1/2 pound cooked per person with a 35 to 40% loss in weight while cooking. Extra is good you'll always eat it!
9 lb. butt = 5lbs cooked = 10 non-teenagers
That's how I figure, bigger buns bigger amounts, smaller buns means they'll eat two.....LOL
It freezes and reheats well BTW, tamales, on baked potatoes, empanadas, pizzas, etc etc etc......