First, there are a LOT of people who don't eat ham or pork. Some are low salt, some religious, some social. Sliced chicken or turkey costs about the same and has higher general acceptance. So consider either doing 60/40 other/ham, or all other.

In addition, there are a lot of gluten free eaters around these days. You might consider a tray of clearly labeled gluten free sandwiches.

And maybe a loaf or empty buns with peanut butter and jam available for the skeptical kids in the bunch.

If you will go with slider buns, some people (and most kids) take 1, many 2, a few 3 or 4. Generally, 12 sliders will feed 5-6 people where 6 full size will feed 4-5, so you gain a bit with the smaller buns. Each of those takes about a pound of meat.

So, following my guide to sandwich making on this site, allow about 20 pounds of deli-sliced/shaved meat and 7 pounds sliced cheese per 100 adults. Do make at least one platter of cheese only for any vegetarians. 2 teaspoons mayo or mustard per full size sandwich, or you can put squeeze bottles on the tables.

It is attractive to allow a gallon of pickle slices on the side for each hundred for sandwiches. Chips, about 6 pounds potato or 8 pounds corn (corn is good in these gluten free days).