(Stikpusher, the latest issue of FSM has exactly that slippery slope in the form of new Vallejo paints for simulating lighting on particular panels of a tank model. I don't advocate going to that extreme to paint a model.)
Thanks for your comments on XF-76, jgeratic. Tamiya's own print media portray their XF-76 as being very green, virtually devoid of any sort of honey or amber color, warmth, etc. If XF-76 is even within the range of perceived colors projected by the paint of the real planes, it is at the extreme green end of that range. I am trying to give Tamiya the benefit of the doubt here. Even if I used acrylic, I would not choose XF-76 for the exterior of a Model 21 Zero.
I read that XF-76 is matt, which would be another reason it does not match. The paint on the pre-July 1943 Model 21 is said to be somewhat glossy, and indeed the very same naval officer said it was somewhat glossy as of February 1942 (in a report, the title of which is abbreviated to "KuuGiHou 0266").
It is also not a match in that one could not paint a panel repair on a real Model 21 with Tamiya XF-76 and expect it to blend perfectly with the factory-applied paint, simply because it is a different sort of material. (I say this with 40 years of automotive background, knowing how difficult it is to repaint part but not all of a car body. If I were to respray a car door with Tamiya or Model Master or Vallejo model paint, I could not hope for it to match the adjacent factory finish.) I could get close, however, for the purposes of some lighting and angles. This is what modelling must settle for.
(Years ago, I published my own partial rebuttal to Mr. Lansdale's early article on the colors of the Zero, seeing that his article was already starting to cause confusion in the modelling world. It appeared in an Asahi Journal around 1999, and is titled "When Light Gray-Green Isn't". Nick Millman was a subscriber at the time. Some of what Nick has said on the subject since then is very similar to what I wrote but it is not credited to me. Nor does Nick tend to credit the Japanese researchers on whom he sometimes relies for his writings on this and other topics, such as Mr. Owaki, Mr. Nohara, Mr. Kurosu, "Mr. Summer" and others. It would be a pleasure to see the Japanese researchers get their due, for a change, in the writings of Westerners.)
I saw Nick's aging progression a couple of years ago. While I think he has the right general idea, I do not think he has taken the oxidation process far enough toward a pale, neutral gray. We know from the color photos of a wrecked Zero on Munda taken maybe mid-1944 (one or more of which is from the Jeff Ethell collection) that the paint on that particular wreck has a thick layer of whitish oxidation at the top. It represents maybe 12-16 months under very intense sun.
Nick apparently had a particular relic in mind when he wrote, "...protected from light and exposure for many years...". That must refer to underside pieces, because certainly the upper surfaces of a plane are not "protected from light and exposure". On the contrary, any paint underneath the oxidation layer of that Zero wreck on Munda had by the time of the photograph been heated by the sun a great deal, day after day, and possibly irreparably damaged by it. Even without that sort of repeated baking, some paints and other materials yellow and brown with age. Is this news?
The problem with Nick's chips or anyone else's, and the pseudo-science revolving around relics, the color measurements, the use of Japanese color words, and all of the other pencil sharpening to find The One True Color, is that there is not just one true color. There is a range of colors we would see from the one paint, which I believe makes obsessing over any one of them unproductive.