Help, please!! My friend just asked me to do her wedding cake, and I want so badly to do it for her, but for one, I've never done a wedding cake, two, she wants a topsy turvy style to feed 200 people! (and no, haven't tried a topsy turvy cake b4 either!!), and three, wants it to be all buttercream! AAAAAAAAHHHHHHHHHHH!

Anyway, my first of many issues is how do I figure out the number of servings on a topsy turvy style cake? Since each tier is 3 layers of cake, and those layers are in graduated sizes, how do you determine the servings?? I know she wants 4 tiers total, but I'm not sure what sizes I need to have the 200 servings. Any advice, please let me know!!

Thanks!