Originally Posted by MikeyB
a thin layer of microscopic cones all over the surface
Reminds me of the surface of an anechoic acoustic chamber. It will look great when new, but won't last long as it's going to be almost impossible to clean:
a) any physical contact (wiping) will take the tops off the cones, permanently degrading the coating;
b) contaminants will end up stuck between the cones, especially sub-micron dust which will result in the surface looking 'grey' and impossible to clean.
Maybe ultrasonic cleaning will work, but I haven't seen an ultrasonic cleaning tank big enough for a refractor objective let alone a corrector plate !