I just tried an experiment where I painted the Left Cowl panel sections pure black (x'000000') in both Spec and Power maps, and took comparison screenshots to my original Spec and Power maps, at the same angle, distance, and time of day - there is virtually no difference in the glare from the cowl panels. I *should* be able to control the definition and intensity of the glare with the power and spec maps, but it appears for some reason I can't. I suspect its the same cause the affects our experience when using the color white on a skin - using too light a base color just seems to overwhelm the spec and power values.
I don't have an answer for why I feel like I have some control on the inner boom sides, though...
Also interesting in Fugi's pic of the B-29 cowls - even though its not polish bare metal, I can see some reflections of the surrounding area in the metal surface...