About two months ago my cousin contacted me and asked if I would cook BBQ and baked beans for her wedding. I agreed. She said she would have 100 guests so that's what I planned for. Thankfully there are a couple spread sheets out there that can help
calculate how much BBQ will be needed for an event depending on the size of the crowd. I also have the benefit of asking those who cater often, through the BBQ Brethren Forum, about the amount of food needed.
My two biggest worries for the wedding were; 1) not having enough BBQ, 2) not having enough sauce. I had cooked 40 butts for a church fund raiser about two years ago and ran out of sauce.