I have someone who will build me cupcake stands, but i need to figure out dimensions of the actual stand to fit 17-18 dz cupcakes all together. The top tier will have a 6" cake on top (so a 8" round top tier), so i won't be able to fit any cupcakes on top, so that leaves me with 4 tiers to fit around 216 cupcakes. What are the next 4 tier sizes i would need? is there a website that has this information? also, they will be round. Thanks everyone for you help!