I have just finished a pattern plane ( the Bernie) that has a SIG 12" canopy.
I painted the interior with a gloss black spray paint. I misted on 3 coats to get an even coverage. The result is a very beautiful gloss black canopy with no chance of the paint being affected by fuel, exhaust residue or plane cleaner. It is opaque, so it is not a tint. Good luck& happy landings Tony