Sorry, new at this game! Can you suggest what size cake I need. Friend wants a cake to feed 60-70 guests (christening) but only wants a single layer square or rectangle! Thanks in advance!!

A 4" high 10" square feeds 50 and a 12" feeds 72.

http://www.wilton.com/cakes/making-cakes/baking-wedding-cake-2-inch-pans.cfm

http://www.wilton.com/cakes/making-cakes/baking-wedding-cake-2-inch-pans.cfm

Single layers serve half of what the two-layer chart shows.

A single-layer 16" square serves 64.
A single-layer 18" square serves 80-81.
Two 11x15" (1/3 sheets) side by side serves 74.
Three 9x13" (1/4 sheets) pushed together serves 75.
Three 10" squares serve 75.

I'm sure you can come up with other custom combinations.