arright...im making a roller coaster box bout 9 feet long 2 feet high and a 4 foot flat before it bends down and back up (rollercoaster) i was wondering what i shood use as a top sheet material...i wasthinking galvanized steel becasue its strong and duz not rust...as long as i bend he metal over the edge it shood not rip bases up...or what type of plastic like LEXAN or a fiber glass thing