I'm ordering a ice cream cake from Friendly's for my nephew's 2nd birthday.

To serve 8-9 adults, 3 kids and 2 toddlers (2yr).
I *might* get a sherbet or frozen yogurt pint for one nephew instead because he has a egg allergy. He can eat some ice cream but not others.

Would you get a round cake that serves 12-15
(anyone know the diameter of this cake?)

OR

A sheet cake that serves 16-20?

My freezer will likely be very packed so I don't want to get too big of a cake with no means to store leftovers. Other wise I'll just buy big so we can have leftovers.