I'd recommend looking in the phone book for a shop that sells exclusively automotive paint to shops. Ask if they have the camera color matching. My Goldenrod Yellow bird needed a few drops of touchup, and the match was close enough that you don't see the spots unless you are really looking for them. The paint supplier didn't charge extra for the color match; the body shop I visited first wanted $35 to do the color match, and they just take the car to the paint supplier for the match!

As for formulation, although the car has an old lacquer finish the paint supplier recommended a PPG urethane touchup with a clear coat. Sounds weird, but it came out great. The two bottles cost $25, and I have enough for several touchups.