Okay Soul Hunter. Do what Smokin' says.
This will be a learning experience for you. This might turn out like one of those old Marine Corp. commercials where they make men out of boys.
This amount of volume will mean a lot of work. It will cease to be fun after the first 4-5 hours. Less if you don't have help.
You MUST presale, then cook about 10-20% extra for stragglers. If you run out great! I do a lot of fundraising and churches are full of optimistic people that won't be around if you're sitting on 200# of extra meat at the end of an event.
As far as the butts are concerned, it sounds like you can get all you'll need on one load. I would schedule a pickup window of no more than 2 hours(1 being even better) and pull directly from the hot smoker, wrap, and deliver to buyer. If you decide to cook earlier and then have to cool, you'll need serious refrigeration to cool that much meat. Think walk in cooler type. Most churches don't have this level of equipment.
Also, check your prices on meat. I don't know where you're located, but I can buy butts in case lots for $.90 per pound as of today from Sam's club or BJ's Wholesale in NC. That's about $.20 per pound less than their marked individual prices.
A far as wrapping a load of ribs, I would disagree with Smokin a bit. I would get a 120qt cooler and pull the first batch off and place directly in the cooler with about 5 gallons of heated sauce. Then post a guard to keep it closed until the next batch is ready to come off. 40 racks of ribs in a closed cooler will still be too hot to touch 5 hours later, and you avoid the tedious wrapping. Pull ribs about 85-90% done because they'll cook a bit more in the cooler, and you don't want them falling apart.
EDIT: Not to seem too cynical, but I can't overstate how important it is to confirm and verify ACTUAL presale numbers. I don't want to use the term "lie", but lets say I have been misinformed on more than one occasion as to the number of presales, sometimes by a factor of 10x. If all they've presold is 30 butts, cooking 150, or even a 100, is out of control wishful thinking and wasteful. You need to see proof of presales and then you decide how much extra to cook.
EDIT #2: I just re-read Smokin's last paragraph and it sounds like he has been the victim of wishful thinking before also. Church groups tend to think backwards from "We need $2000 dollars for our youth group, to we'll make $20 per butt sold, to we'll sell 100 butts and that will solve our problem". This cook it and they will come mentality is good for churches and bad for caterers.