HI!! I know this may be a lot of work but I suggest using a big PVC pipe screwed to a wooden board (which is covered with wrap and tissue). Your cakes will be slided on this pipe and use dowels inbetween cakes as well. Don’t hesitate to ask me for further details if you wish.
Doing this will give you a solid cake and save you money!
President of Gateaux Duchesse.... Blog:http://gateauxduchesse.blogspot.ca