If I had to do it, I would do the front , top and back with one big sheet like you said. Then I would do one long skinny one to cover the top and sides. It would be a double layer on top but, you wouldn't have to worry about sliding. Then like someone else said the rolled border would cover all seems. I can't wait to see how it turns out, it's going to be so cute!!
Thanks , that does help. I guess I'm not sure if they are to be eaten or not. Also, are they supposed to be hard like royal icing when they dry ?I have never used MMF so I really don't know anything about it.... thanks for any help!!!