Don't know how I missed this!
Great work and scheme- very neat (which always gets a bonus 10 pts from me!
Can we get a close up of the toe- how did you weather it?
I will try to get new pics up this weekend, but the quick answer is that I used watered down Citadel Badab Black ink and just layered it on in the areas you'd expect to see weathering and chipping on the toe. I then took some thinned down VGC Black paint and hit just a few areas to deepen the black to a level I couldn't easily get with the ink. Finally I used VGC Gunmetal (GW Boltgun Metal) to add the paint chips.
I'm still experimenting with this method, though, so once I get it somewhat nailed down I'll post a more comprehensive tutorial. I was also looking at using some weathering pigments I have to add dust to the models, as well as using the Citadel Devlan Mud to create some rust/oil streaks.