When I originally built the panels and cradles for the 4'x8' piece I didn't reinforce them, I didn't think I needed to. Well over time and when they got wet from adhering the paper they became extremely warped.
So today I tried to straighten them back out in hopes they will lay flush with the wall when it hangs in a gallery or someones home. Besides adding center supports, I added corner braces to both. Then I weighted down all 4 corners so that overnight it will force it back in to shape and flatten it out. If this doesn't work Im not sure what I will do to fix them. I also got in a little painting today too.
Update 6/10/14: Well the fix worked, Yaaaaaaa! Now they lay flush with the wall. I need to paint the backs black, clean up the sides and make sure all the paper is down on the edges, Work the front a little bit more and sign it. Then I need to photograph it.