I made a topsy turvy cake for a friend's baby shower cake a year ago. I bake 2" tall tiers. I cut the tier so the one side was 2" tall and the other side was 1.25" tall. I used 3 layers in each cake, so the cake was 6" tall on one side and 3.75" on the other side.
I followed the advice given on Sharon Zambito's DVD. I know you don't have time to order the DVD for this cake, but I think she now has an option for download. You might want to check it out.