Pork Loin Shrinkage

We are doing a backyard contest/festival in a couple of weeks, and we were looking at doing Smoke Pork Loin Sandwiches. We have a bakery here that will give us a good price on french rolls that are just a bit bigger than slider buns. We're looking at about a 2 ounce slice on a roll with their choice of barbecue sauces (Sauces in squeeze bottles for them to choose from)

Sounds funny - but I can't find any real good estimates for pork loin shrinkage. Just from what I've done I'm thinking it's about 20%. What have you experienced? Looking at serving 400 (recommended by the festival) so I'm thinking a total of 7 pork loin @ 8 lb average weight. Sound reasonable?

Any input appreciated.

Thanks poorolddan. Organizer told me 400-500, so took the lower number. He also gave me the portion size and the price is set by the scrip the organization is selling (I don't see any of that money - this is basically a donation to the volunteer fire department. Unless I win ) - but I like the idea of 2 slices for a total of 3 ounces. That works for me so think that's what we will go with and just go with 8 pork loins.

Bob - will look into that Pork O Nator. Sounds like a neat idea.

Will get some picks from my wife - but things went well. Did 7 9 lb (average weight) pork loins - took about 4 - 4 1/2 hours for all to hit 155 IT. - pulled, wrapped in foil and place into a cooler as they hit the temp.

took poorolddans advice - nice thin slices placed onto a littler larger than slider size French roll (about 3 ounce servings), choice of 4 different sauces. Served about 250 sandwiches in 3 hours - the last hour was during a thunder storm that got pretty nasty, so it was pretty slow. Had a number of people come back for seconds ( a couple came back an got multiples to take home) Wound up with 1 loin left - and pretty sure if the weather had been better we'd have sold out.

Over all for a first time vending any type of event, it went pretty well.
Thanks all for the input!