
Excellent post Champi!
To answer your question about the SBD's cowl ring; the screenshot above illustrates the difference in lighting between the cowling panels, and the cowl ring, or nose. It does not matter what color is used, it's always there. And most, if not all, my SBD based paintjobs even feature a slightly darker cowl ring in order to compensate for this effect. But even then, it still appears lighter, as evidenced by the screenshot. So why not make it even darker? ..well, if this area is viewed from a different angle, it often becomes the same shade as the remaining cowl panels, or even darker. So what I finally did, was try to strike a compromise with the shading.. otherwise, as I mentioned before, it becomes an endless process of adjustments.. back and forth between light and dark.
You spoke of 'planer v cylindical' mapping regarding this area, so perhaps that is the culprit?
Of course, not being a modeller, I don't know if this is something that could have been corrected during construction; or if it's due to the drastically opposing angles, and nothing further can be done about it. All I know, is that it's always been a tricky feature to skin around. And when we don't like skinning a particular feature, it's always easier to blame the person/s who did the modelling

Anyway, Thank You for taking the time to put all those examples together, well done!