To me it looks like 2-10" cakes and 2-8" cakes, but if you wanted to smaller you could do 2-8" and 2-6". What the gray part of the tower looks like to me is a upside down terra cotta flower pot covered in fondant (maybe that's what they did. Line a flower pot the size you need with cling wrap, pack in some RCT , and pull it out once it's "molded"...cover with BC and add your fondant. Top could very well be RKT as well.