If you can't get an exact match, then my suggestion would be to go the route of the body shop.
Alternatively contact Hiroboy, he may be able to help you get a paint color match.
Which F1 car are you working on, maybe a forum member can help?
And if this is for a model car then of course it belongs here
Just wasn't sure why you were asking about Sikkens here as I don't believe they're in the US.