Flat Car Deck Weathering

I was looking at a few of my flat car models recently and found some of the decks to be rather vanilla or monotonous looking, like the one shown above. I decided to try an experiment on a couple to see what I could do to improve things. I took the SP F-70-7 shown above as well as an I-GN 50-ton AAR flat car that I finished a few years back, based upon the stunning Pittsburgh Scale Models kit. 

Using artists' oils thinned with mineral spirits, I highlighted individual boards in various shades of greys, yellows and reddish-oranges (grey, umber, sienna, ochre, etc.) on both decks. Yes, they look starkly different at the point of these photos. The I-GN deck is illustrated above, while the SP is shown directly below. They are laser cut wood and styrene, respectively.

After applying the oils, I sealed those with a coat of Tamiya XF-86 clear flat, thinned and airbrushed. I then blended these various boards through application of PanPastel Raw Umber, Orange Shade, Yellow Ochre, and Yellow Ochre Shade followed by Bragdon's Grimy Grey. Everything was again sealed with the Tamiya clear flat coat.

I think the final results look suitably variable without too much differentiation. I also think that the photos do not convey the overall feel as well I would have liked.