Hey Bernard.
I'm not 100 percent sure about this, but my understanding on the two shades of gray colors you mentioned were used on the later A6M Zeros. Nakajima had one shade of Gray, and Mitsubishi had another gray that was a little different. These manufacturers also used a slightly different demarcation line on the side of the fuselage on the Zero, between the green and the gray colors. Nakajima used one style to break the colors and Mitsubishi used another. The same was true with the cockpit colors... Mitsubishi used one color, while Nakajima used another...
I agree, confusing to say the least.
There was a whole set of colors used by the Japanese throughout the War, ranging from various shades of red, blue, yellow, silver / aluminum, greens, browns etc. ... It was pretty comparable to the set of colors used by the US or even the RLM with their unique numbering system.
From what I have gathered by looking at photos of relics and souvenirs from crashed or shot down planes, the Ame-Iro color actually held up pretty well, as long as it was not exposed for a really long time to the elements. One "Ame-Iro" photo I saw actually had a watch held up in the reflection and you could see the watch pretty clearly in the reflection of the paint. It was a fairly glossy finish to begin with. But as any paint will do, the color would start to become chalky in appearance after a while.
There is a lot of debate as to what colors were used and when. This is only my perception, and may not be 100 percent correct. But I really think it's pretty close.
Also German RLM 02 is a fairly close match to "Ame-Iro". But then again, it all boils down to lighting, photography methods and the condition of the actual sample used for a comparison.
Some samples actually started to shine again after a little polishing...
Freddie, after looking at how nice your plane turned out, my kits are moving closer to the top of the "To build soon" pile... If the Ki-51 Sonya is as nice as this one, they will have a winner on their hands. I'll have to get one... or two...