I'm making my first topsy turvy cake, it is for aprox 30 people. I was wondering do you have to make each tier with 3 cakes or can you use only two cakes on each tier? I don't want to make to much cake or to little. Also any suggestions on cake sizes. I'm new at this if you can't tell. but loving it so far.

there are several different methods to do a topsy turvy

the first is in Dutch, but you'll get it by looking at the pictures

http://www.deleukstetaarten.nl/forum/viewtopic.php?id=19855

http://www.sugarcraft.com/catalog/wedding/whimsycakes.htm

as you can see, these people doing it with one cake, approximately 4inch high

Thank you tipsytaartje, your reply was a great help. I wasn't sure it it would look good with only two cakes in each tier since all the tutorials I've seen have had three cakes in their tiers. The tutorial you listed only has one cake in the bottom tier and looks like 1 1/2 for the other two and it still looked great.