If you have the option, call the place you're going to buy them before heading down there. Ask them if they'll cut you a deal for buying in bulk, that is, unless you are getting them from Sams or Costco.
A half slab is good, get some chicken leg and thighs for backup they are cheap and you might have leftovers. Actually a 1/4 slab and a chicken 1/4 is a great combo. I served that in my restaurant and it was a hit.