There is no 1-2-5% figure, there are to many variables in this business to get a good feeling on sales. The only thing I can guarantee is, Monday morning you will have all the answers. I would always build my menu on items I can run to the store and buy on quick notice. This will give you a good feeling of knowing, if the **** hits the fan, your a few minutes away from survival. You will have some vendors that will have killer menus, and others that just fill in. How could any one say, they could figure out a percent to the total attendance is stupid. Keep your perishables low, and always have a plan for the leftover items……………………Bill
 
You menu also has to many menu items……..
Taco shells
lettuce
tomato
onions
chili
Jalapenos
 
Hot dogs 2 sizes
Brats
Kraut
Shredded cheese
hamburgers
sliced cheese
ketchup, mustard, relish  and so on…………………..The lettuce, tomatoes and onions go on both the Tacos and burgers. The bad thing is they are fresh and hard to figure out the amounts needed. They are also items that can be bought at any food store. I would do a 1/8 shred on lettuce, it will work out well for the tacos and burgers. The onion can be chopped for all menu items, tomatoes will have to be sliced and chopped…………….This is a Salsa fest, I would figure everyone attending would decide to eat something. Its not like a craft fair where people go for the crafts and the food is secondary………………….May as well offer a “Chili cheese burger” ?????????  good luck, wish you the best……….Bill …P.S I have the luxury of over buying, “to cover my clients needs”, and sending back all unused food items.