Side dish quantity

It sort of matters how much meat and what meats. However, rule of thumb for me...

1. Go heavy on Mac-n-cheese, you will want the two pans
2. Go light on slaw, you can get away with one pan
3. Beans are really cheap, unless you go nuts, make the two pans

I just rarely have seen the slaw run out. Mac-n-cheese always runs out. Beans are a funny thing, some gatherings hammer through them, others don't touch them.

I think your "50 rule" is correct for full pans. I do half pans=20-25 people, based on who it is and what else is being served. I always have have leftover beans even though people like them. If I were you I would make one full pan plus a half pan (or 3 half pans) of beans.

I'd go 6oz on the mac n cheese, 3oz on the slaw and 2 pans of beans made from 4 10# cans doctored. Place the beans, 1st slaw 2nd and mac 3rd. I am a firm believer that placement on the buffet matters.