If you havent released this beauty yet, I have one suggestion that may add more depth...its one of my little secrets hehe.
Depending on what program you are using (I use PSP) take the lightness down tool, set it at 100 percent density, 22 opacity and a step of 25...go for size of the tool to be about 50 percent larger than the gaps between each panel...the dark lines you have running between them. I found 64 is a good size, sometimes it needs to be smaller or larger.
Then very carefully use the tool, dabbing a bit at a time along the line to darken that area..it will overlap on the panels slightly.
This will REALLY add to the overall look of the panels, giving them much more depth and weathering without bumpmapping.