I'm helping my neighbors out with making her sons birthday cake. The theme is Pokemon. I want to do a couple of frozen transfers but not sure which on is best to use, Buttercream or Royal Icing. Some of the transfers will go on top of the cake and some will go on the side. His party is not until the 22nd so I have some time to practice if I need to.
I would do buttercream transfers. You can do them well in advance and just apply them to the cake when you're ready. If you choose to make a royal icing transfer, I wouldn't put it in the freezer. The moisture will soften it, unless that's what you want so you can put it on the cake and then have it dry hard. I've never tried that method. In fact, I've never done a RI transfer, so i can't really say how that will work. I do like FBCT for their easy of doing in advance and applying to a cake.
I'm sure someone else will have some sage advice.
Royal does NOT freeze. If you use royal you would let it dry at room temp for about 24 hrs then it can be stored in a clean, dry box (non-air tight). This would be a good way to do those you want to go around the sides of the cake. Dry them on the cake pan so they take the rounded shape.
They WILL be *hard* when bite into.