I am doing one for a child's birthday party...what size cake do you use so that Kit Kats extend over top of cake? I have never made one but love the idea. Thanks for you help?

I used the full size - they sell 6-packs of them in the candy section at Wal-mart (not the checkout or the Halloween section) for a better deal.

sorry you misunderstand. What size (height) of cake do you use. One layer, two layers, 8 inch, 9 inch cake? thanks.