Where you been hiden CB!
I think the answer to the cars(after seeing the pictures), and reading all the stuff, is to perhaps paint them a slightly brighter shade of maroon, or red than you really want. This way when it fades or weathers it will be the desired true color. In the meantime they will look bright and stand out. Maybe slightly darker than the current ones would be closer to maroon. Of course as cars are repainted some will look a lot different!
As for the authenticity, as I stated before, it really doesn't matter on these cars anyway! So, go for the new color, and maybe keep a few of the green for specials, since they were the color
during the San Juan period, and another way to represent the many time periods of the old Rio Grande color schemes throughout the railroads lifetime.
Steamingly,
Greg Scholl