Flowers vs. Table Size

Can anyone help me by posting pictures or give advice regarding the following question...

Seems as if I have 3 circular tables choices...

60 inch 8-10 people
66 inch 9-11 people
72 inch 10-12 people

I want to have low glass cube centerpieces..but not sure what size cube I should have.

Can anyone give me any advice or post different pictures of flowers on circular tables - specifying what size table?

Thanks so much!!