I will be cooking Boston Butt (no bone) for my Son's Inner school family night.  There is expected to be upwards of 500 people however I have been asked to make sufficient pull pork for about 150 parents and students.  I will be using about 70 lbs of heritage pork and will be cooking them on my 2 Star and my green egg.  There will also be hamburgers and hotdogs etc.  This cook will take place this coming Thursday and finished on Friday morning.   Any thoughts or ideas are greatly appreciated.

Plan more time than you think you need.  If you finish early, it will be easy to reheat.  I usually plan 1/2# uncooked per person.  I would think you could fit most of that on the MAK if you have upper grates.  I think you can fit 8 shoulders on that grill.

I don’t see where you factored in any weight loss on you cook!

Monster cook. Better to finish early than other way around

Agree with this statement - have a bunch of coolers and foil ready as you can finish 3-4+ hours early and hold them until your ready.
Sounds like it will be a fun time!

FWIW, On my latest butt cook (28lbs.), I ended up with 55% of finished product which included 3-4 cups of juice being added back.                   

You sound perfect for amounts.  Assuming you get 55% and with boneless I thin that is a real good assumption, you get 4.1oz of cooked meat/person, add in a little sauce and that is a Big sandwich!  Hope they have been on quite awhile!