Has anyone done a cake with tall tiers that are dummy on the bottom, cake on the top?  I'm doing a 12"-9"-6" and I want the bottom two tiers to be double tall (8") but I don't need that much cake.  I'm assuming this will be fine, I will put a cake board under the cake on top of the styrofoam, securing the cake to the styro with skewers, supporting the top tiers with bubble straws and a dowel in the center of the whole cake.  It seems like this would be common, but I can't find anything in the forum about it.  I just want to know if anyone has done this, if there are any pitfalls I should be aware of?

Hello??? I need advice, no one has done this before???