First BIG cook questions from a rookie.

Pork butt would probably be the easiest to deal with, it's pretty foolproof. I'd figure 1/3 pound of pork per person, if you're planning on having sides. That would work out to about 66 pounds of uncooked meat (figure on a 50% loss) for 100 people.

You are probably going to have more meat in your cooker than you ever have had before. Be aware of how the extra meat will impact your pit temp and plan accordingly. Do not cut times too close. You can always rest the meat.

Get some volunteers to be your assistants. Kids are great for that. You don't want to forget that you were in the middle of something because you had to run and grab something.

Bets of luck!

Also, if you are cooking things that come off at very different times, figure in some more time for the large cuts from opening the doors a bit more often.

Make sure you have some extra coolers available and plan to have plenty of extra time. If you get the pork done way ahead of the chicken that will make things much easier.

You can foil, wrap in towels, place in cooler and the pork shoulders will be safe for hours while you work on the quicker cooking chicken, likely at a higher temp.

Good luck man! Sounds like you have your work cut out for you.

I would go with the previous advice. Get that pork done, and rest it in a cooler. I've rested some for nearly five hours and it was delicious. Then raise temperature and cook that chicken next. You might use the smaller grills to keep little appetizers going like MOINK balls or ABTs.

I cooked PP for 125 people on 3 UDS's, cooked them overnight for roughly 12 ours at 225, rested them for almost 5 hours while the beans and other sides where cooked/prepared, it all turned out delicious and he PP was almost as hot to pull as when I pulled it right off the cooker. Take your time, have plenty of help and it will go a lot better than you think. I am also in the process of building a 175 gallon fuel tank grill , I think I am going to make it a vertical cooker but am going to try to build another box on the inside and make it an insulated vertical cooker.

Hero Time

High School grad party for my son I cooked for 54 adults and too many kiddos to count. Lots of folks eat standing up and grazing. I did the ribs, resmoked a cure 81 and three turkey breasts. White bread, Italian bread, Kings Hawaiian rolls. All easy cooks. During the peak I had BBQ chipotle meatballs, margaritaville shrimp, ABT's chips and dips. Sausage in white bread with slaw and a BBQ sauce is tasty.

I did not serve any alcohol although I had a secret stash in the washing machine in the utility room for me and one brother.

You want to stay busy but not too busy that you can't enjoy the event also. People to watch for

Weird uncle frank: make sure he minds his manners
Crazy Aunt Nancy: remind her it is NOT her party, be brutally honest if necessary
Ghoulish Grandma: all old folks have basically are their memories but try to avoid letting her capture innocents with stories of the dead and the dying.

Pray and good luck