Well now, I guess it would depend if you have bone in or bone out? Let's just figure they are bone in,good kind to buy! After cooking to an internal temp of 195* and a probe slides in and out with no resistance. I'd guess about 5-6 lbs of pulled pork, maybe a little less or more, depending on if they were enhanced PB's to start with, those are bad!
I'd figure on 4 sandwiches for a pound of finished meat, no sense in skimping.
You're welcome!