How many ounces should a plastic punch glass be?

How many ounces should a plastic punch glass be? They sell them online from 2 oz. to 12 oz. I think. I need them for my wedding.|||It depends on the glasses you use. The most commonly used are 8 oz. Guests can always get refills as they wish. 12oz is a can of Coke and too much for one serving.|||I would go with 6 oz. They can always help their selves to more punch if need be.|||5oz are the size of the larger dixie cups so I would say that is too small. 8-12|||I would go with 8 oz.