I'm teaching a class on Thursday on how to decorate cupcakes. There will be about 20 people there, and they are supposed to bring 6 un-iced cupcakes. I'll bring icing for everyone to use, but I have no idea how much to make. I'm only a hobby baker, so I don't usually bake in bulk. I'm going to teach them how to do the swirly cupcake like you buy at a bakery, and I'm going do some other cupcakes that are dirty iced with fondant or another decoration on top. Any suggestions?