Have cooked for the military several times. Cooking/serving ribs at a volume level will require a large volume of rib racks... because you want to maximize the amount of meat per square inch of your smoker.
Will take 300 lbs raw pork (40 butts) just to cover 500 sandwiches.
Custom Klose Backyard Chef... of Snot, and a 22.5 WSM
Lang 84 Deluxe kitchen, Lang 60 Mobile - The Damsel II, Lang 48 Patio - The Damsel, Bubba Keg Grill - RIP, Double Barrel Smoker and a BSKD