Go to your local automotive paint store (that carries Dupont) with the bike and have them "eye match" it for you. They use a digital camera computer placed right on a painted surface to take a picture and run it to a data base. Eventually, they'll come up with a code of their own so you can duplicate the tint as you need it.
It might be tricky as the bike has a low gloss finish but one could always use some clear tape on the paint to emulate a clear coat finish and thus, get a true reading by the camera.
I use this process regularly in my body shop business to get correct color matches...