Yeah it is actually pretty easy to do, if you dont screw them up lol. I was toying around with the idea of not even painting them. I thought about using my spare lenses to test some vinyl out on. I would just have the vinyl cut to the specs of the lenses and with the holes already cut to spec as well. Then just clean and put on, No drying time and perfect circles.
I actually made a detailed layout of how they should go on. I know it is kind of hard to determine where to put the circles in the begining. I figured this would help eliminate the guess work.