I want to do a birdcage cake using 10 inch rounds. I would like to stack 3, possibly 4 using the SPS between each two layers. I would then like to carve a top cake for the dome. Is this too much weight for one cake? I would use a cake plate or board between the dome and the top two layers. SPS if necessary. Any ideas or comments would be greatly appreciated as I always tend to want to make cake defy the odds! Will be traveling about 30 minutes away with cake.