This sounds like a lot of fun. Eventhough I don't go to school I still love all that stuff, and any way christmas will soon be upon us. I live in Australia and our school year starts in February and I have a lot of friends with kids at school so count me in.
I put an old folded up towel underneath and then between each sheet of paper I use different pieces of fabric and then I can peg these up to dry. I use old tea towls the most, some smooth and some textured depending on the effect I want. A tip to help avoid the smooth shiny side. place a piece of cloth between the formed paper sheet and the plastic.