I always figure losin 50% a the raw product, most times it be 40%, but better to error on the side a safe. I serve 1/4 lb sammies which is more then fallin outa the bun.
So, doin the math:
15 pounds raw
7 1/2 pounds cooked
1/4 lb sammie
equals 30 sammies
You know the folks, is 30 sammies gonna feed the 24 folks? Kids won't usually eat more then 1, but when the adults taste it, is one sammie gonna feed em? Men folk gonna eat more then women folk to (usually).
But this give ya an idear what yer yeild will be. Also, whatch yer portions, best ta get a 1/4 pound scoop till ya get the idear what the portions look like, cause ifin they start pilin it on ya run out real quick!
Good luck.