Just for clarification, the amount of layes has nothing to do with transmission, Back Reflection, and Scattering. Its the quality of the one layer you put on. Not really quality, but how well you matched the index of refraction of the air/glass. We coat very small, things like fiber optic film filteres with the same equipment. Some times, we mess up, and don't get it right. Those of course are trashed. But once its setup, you can get thousands of them right. I am not flaming you, I know you were just putting down an informative post.