I bought a sheet from eBay, the new yanke glass. Took a month to deliver, fresnel was scratched and it didn't fit (was half a mm too wide) so a month without use of my Cambo 4x5 and still no resolution. If anyone has a ground glass or has seen a ground glass for my camera, let me know! In the mean time, I wait for the guy to get in touch. Also, unrelated but what would be the best way of shaving off half a mm of a sheet of glass?