See this article:

www.ellenskitchen.com/bigpots/plan/selfservetips.html

For a full meal salad bar, people take a total of 16-18 ounces of food, with that being about 5 ounces of greens and all the rest toppings and other addition. Then they use 3-4 tablespoons dressing (more if thicker). You would use something less with the sandwiches added.

You can use the baked potato bar for ideas and quantities for the toppings.

Then you need bread and crackers, about 6 pounds of crackers or 12 pounds of bread.

You want 4-5 ounces of deli meats and 2 ounces of sliced cheese per person, I don't have a suggestion about the mix of the meats.