My default answer is that you will not (almost never) be satisfied with repro out of the box.
Restoring the incorrect color NOS grille is a challenge, due to the rivets and color match, so I completely "feel your pain" which is compounded considering that you are overseas. If I had a perfect match made for paint, I could send you a formula, but not the paint. The formula would have to be interpreted, I imagine, and the material would be more restrictive on your end, I presume. So I get the interest in differences to repros. Personally I did not go that route so can't talk in detail. Perhaps someone else will chime in.
I'm working with Jeroen on the same thing since he is trying to restore a grille.