Yeah I was planning on painting the bottom of the glass black and also using a standard piece of C2 buildtak. I experienced this obnoxious issue when trying to use a sheet of (orange) Lokbuild. I guess I'll just go the basic route I had originally planned. With the IR sensor there's no real need to level the build surface constantly. I'll just do it once with shims and then epoxy nuts in place to set onto the existing nut on the metal tray.