I'd say it'd be easiest just to head to your local auto paint store, give them your code, and have them mix up a gallon or so for you... I'd think that would be cheaper than buying a little bit of this, a little bit of that...etc. mixing paint properly requires the proper equipment to do right...

You might be able to get the folks to give you a printout of the exact formula they used so you can keep it on file for future reference... I got a copy of that when I had my Jaguar painted.... now if I could only find the damn thing... I got more bits that need paint, and I don't remember the code...
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-Matt I ♥ my ♂