If you know any of the employees at your local Lowes' or home depot you can get some of the packing for the asphaltum covered siding panels they sell. they are styrofoam- 4' X 8" X 6" The front (or what you would make the front) is a wave pattern that conforms to the wave pattern of the siding. 4" on center peak to peak. With these I can get around buying more of those pricey Skyline diffusers. Anyone out there know how to paint syrofoam? Djose