Ceiling mounted UST projector will not work with CLR 2/ CLR 3/ CLR 4 flipped upside down because the material is specifically oriented to reject “absorb” lighting from above.  In addition it is designed to properly accept tabletop mounted UST projector light and direct it to the viewer’s sweet spot. If the material is flipped upside down and there is overhead light, that light will not be rejected but instead reflected which would degrade the picture quality. In addition, the ceiling mounted UST projector light will still not likely align properly with the human eye to deliver the ideal “sweet-spot” picture performance.