My brother has tinted taillights on his jeep Cherokee. Looks great sitting still, but during the day it's hard to see his blinkers and brake lights. Not good on a bike. Maybe if you get some bright led bulbs it will overcome that.
"NightShades" by Sherwin-Williams (VHT) is translucent. The opacity builds with multiple coats. One of the fractions is the same basic chem as is found in the line of plastic "paint" by S-W as Krylon. The lens should be clean using an alcohol wipe after a good cleaning with detergent and water. A couple of coats and maybe three is usually sufficient. Follow the directions on the rattlecan to prevent crazing. The product, if not paying attention to the directions can bite you on the ass. The adhesion promotor as in the Krylon paint bites into the plastic. A second or third coat if the first (prime coat) is not dry will partially dissolve the prime coat. As that coat dries it shrinks over a slick surface and fissures occur cracking (crazing) the topcoats. Great if ya like that effect.. The shit is really hard to get off if this happens.. How do I know this? Not too may pesos for a couple of turn signal caps but on a Lexus... Good stuff on changing oot those bulbs for LEDs. Best to test on a junker lens..