Hi all!
Ok so I have a question for all my topsy turvy ladies/gents out there: I've made two topsy turvy cakes in the past and have transported them using the SPS system (separator plate system). They arrived in one piece however, since almost all my cakes are buttercream, sometimes the ride over tends to compress my fillings in the stacked cakes and an unsightly line(s) appears in the side of my cakes. I do make a thick buttercream dam and I also weigh my cakes down in the fridge over night and I travel with them refrigerated. I would like to know if any of you have ever stacked a topsy turvy cake on site at the venue. Would this be possible? I carve  a level space (tier beneath) for the top cake to sit on to give it the effect of the cake being turvy so I'm not sure if the mere fact that it is buttercream will make the stacking to messy. Please help! Thanks,
Fedra

I think if you have your level spots already cut out of the tops of your tiers, stacking on site should not be any more difficult than any other cake.
Maybe you need to use a stiffer buttercream for your dams. I have delivered many 2,3, and even 4 tiered buttercream cakes with mousse fillings and not had that problem. Yet!
Some folks actually make a dam out of another layer that has had the inside cut out, leaving a 1/2 inch or so of cake that you can put your filling inside. I have never tried that method though.

I have a different way of carving topsy turvy cakes.
I never stack more than 2 cake tiers for transport - especially if it's a topsy turvy cake. I assemble cakes on site. I find it to be much less stressful.

You might consider using more stable fillings if they are pushing out of the sides of the cake. That means they are too loose and not good for stacked cakes.

I'll be the dissenter here.... I never do TT cakes in buttercream (partly because I use SMBC) and I would NEVER assemble them on site. Waaay too high a chance of problems.

I made my buttercream dam thicker which has worked wonderfully with the lines seen on the side of my cakes. I also ended up using the SPS system delivered it stacked. It arrived safe and sound. I have a picture of it in my galleries. I rarely use fondant because I am more practical with buttercream. I have considered fondant before but not that many people in the south like it.

Fab-u-lous!