I'm trying to figgure out how to construct and secure a center backdrop for my N scale layout. My layout is made out of 2" blue foam and needs to be dividied diaonally by a free-standing backdrop. Tight clearances on my layout dictate a narrow backdrop, probably 1/4" thick. What should I use to make my backdrop? Foam core board? Masonite? Plywood? It needs to be 42" long and between 9" and 12" tall. You can see in the attached photo how the backdrop needs to run. It will go along the right side, up against the blue foam bluff. It needs to start where the foam starts on the far end and runn about 6" off the end of the foam on the near end. Any help would be much appreciated!