Travis,
Thanks for the model info. You too grandad.
Regarding the Panzer gray, etc., it all comes down to the personal choice of matching colors or showing a scale effect. I know that spot painting, on the deck, is done with a rattle can of black. But on a model in 1/72nd scale, a standard black paint can to some modelers eye, mine included, can appear too black. Like looking down a deep, dark hole.
I've tended to stick with MM Acryl "Aircraft Interior Black" as a standard for just about everything. Tamiya's NATO Black is another good "not quite so black" a color. Then there are various other "tire blacks", etc., to choose from.
I had some Panzer gray in a rattle can, that you can see on my posted thread on the Aoshima 1/48th Airwolf. I had the paint, and since I was dealing with several different dark colors anyway, I gave the underside of the rotors a shot. Its a very dark gray and blended well with the other dark colors I was using and avoided, again to my eye, having the model look too monochrome.
Of course, this is all personal choice. I build lots of 1/700th scale ships, so I tend to lighten up the smaller scales. I've carried the thought on to my other models.
Other folks, don't care for attempting "scale effect." They go with a straight shot of the correct paint.
If we all did it the same way, it could be a less exciting hobby.
Have fun and thanks again for the Zulu info.