I have a cake that is 4 layers, 10'' on top, then 9'', then 2 8'' layers on the bottom. It is between 7 1/2 and 8 inches tall. Can I cover this cake in one large piece? I think I read somewhere that you can cover a cake in one piece as long at the height doesn't exceed the diameter. But does this count for the top tier which is 10 or the bottom which is 8? Or is it best to wrap it?