Frozen Buttercream Transfers

I have seen frozen buttercream transfers on Pinterest, Youtube, and a few cake decorating books I own. I've been dying to try it because it allows for detailed pictures. I printed out some superhero pictures and printed my message on the computer. I then traced everything onto wax paper, and piped on the buttercream. Generally it was very easy, but here are some of my mistakes...

1.) I forgot to invert the superhero pictures. I couldn't use superman or robin because they were backward.
2.) When I piped the buttercream on the superhero pictures the wax paper was just on my counter. I then attempted to slide the wax paper onto a cookie sheet to then stick in the freezer. Bad idea. My wax paper folded and ruined Batman :-( In retrospect I would have put the wax paper on the cookie sheet to begin with.
3.) I didn't push down the icing enough. After you pipe all the details you add a layer of white buttercream to stick everything together.Then you use an angled spatula to smooth out the white icing and push everything down. This should make everything look solid and not just piped on. I was so afraid of ruining my design that I didn't flatten everything out enough.

I didn't think the writing came out great, so I don't think I would try that again. I have read online to use kids coloring pages since they have basic lines. Try it out and let me know how it goes.