I think this has been asked before but I couldnt find it again. I have to make a topsy turvy cake (3 tier) for a friend to serve approx 40 people. I still suck on serving sizes.

Will this serve (party servings) 40 ppl; 10", 8", 6" round? i am not cutting the sides. Or should I go a little larger?

Thanks for your help. (and yes i bake out of legal kitchen).

any help with this would be greatly appreciated. I have never made a topsy turvy cake.
Thanks