Hello all,,,,Would like some input on what kind of substrate to put lettering on for installing over bay doors at business. The sign will be about 16 inces tall and 8 ft. long. It will go over the doors like " RECEIVING BAY" 1 & "SHIPPING BAY 2". It will have 12 inch letters. Just concerned about warping and that sort of thing. Thanks for any advise,,,,,Paul