Viennese hour - What kind of to go boxes

So my friend has set the date (10/25/15) and booked the venue (Sandcastle)

Now I need your opinion on Viennese hour to go boxes. She got the okay from the venue and I was wondering what size box would be best?

6-1/4 x 3-3/4 x 2-1/8' 100% Recycled Brown Kraft Bakery Boxes (250 / case)

6 x 6 x 3' 100% Recycled Brown Kraft Bakery Boxes (250 / case)

or tell me a size. Links would be greatly appreciated!

We ordered these, they are 4x3x3 and I think they are a perfect size for a decent amount of cookies, I don't know if you could fit a slice of cake in there though

https://www.efavormart.com/personalized-tote-box-100count.aspx