Q: How about using any “CLR/ALR” (Cinegrey®3D/5D or Starbright CLR®/CLR® 2/CLR® 3) with a ceiling-installed UST/ST projector?

Ceiling mounted UST projectors will not even work with Starbright CLR® materials because the material is specifically orientated to reject “ceiling light” or any type of lighting from above. This means that the screen will reject any overhead light, even from a compatible projector. Theoretically, you could invert the Starbright CLR® material to match with an inverted UST projector but the alignment will still not likely align properly with the human eye to deliver the ideal “sweet-spot” picture performance.