Well, there are 8 ounces in a cup, the "regular size" can of beans is typically about 14 oz. The bigger size of Bush's beans is 28, that's my normal size can. I will be doing a double butted feast (2 half pans) with a half pan of beans, one of Mac and cheese, about an equal amount of potato salad and myriad other sides. That will be ample for the 20-25 I expect. A half pan will end up holding about three of the 28 oz. cans and the associated smacked sausage, onion and other doctorfication.
I find it very easy to overthink anyone of these feasts. I am sitting on my hands this year, if it all fails, I will go back to thinking about this in March!
Don't sweat having too much, as long as everyone has fun it will be a success!
Good timing is best, the smarter you work, the less frustration when it comes to plating the feast. I try to have everything pretty much ready to go a half hour early to account for my own shortcomings and early arrivals!
It will be fine.