my guess is a 6 and 8 inch.
Most likely as the other poster said, BUT........ What size do you need - how many servings?
The cake/design can be made in many, many different sizes depending on how many servings needed :)
AI need it for about 50-60 people?
I would go with a 10 inch and 8 inch, it should feed 62 people.
how many layers do you think?