I'm also looking at highlighting my black on the armor plates, I have Fenris Grey and Shadow Grey (VGC Sombre Grey) to make a more blue hued deep grey, Codex Grey (VGC Cold Grey) and Fortress Grey (VGC Stonewall Grey) for a more pure grey highlight, and VMC German Grey and VMC Dark Grey for a very dark grey color. I'm also looking at mixing black with any of the above to move from black to any of the above.
Any thoughts? I'm not wanting super-bright highlighting, but I'm thinking that just going from black to 1:1 Black:Fenris Grey then pure Fenris probably wouldn't be that great. What do people think would look good for the black highlighting, I haven't actually done any black highlighting at this point.
Excellent work BB, really nice grimdark paint scheme and tidy paintwork.
Your repainted termy is first rate. I like the effort you put in to the 'gem' style eyes and lenses. Also the fire painted on a few of your vets shoulders is cool.
As for highlights, have you tried just using gunmetal lightly on the edges, it looks great on vehicles and would probably look equally good on dark termies. kind of like battle damage... Fortress grey is also a good highlight colour needs to be applied with the edge of a brush to keep it from being glunky though, you're up to it I'm sure.
On the down side your bases are way too plain for such well painted models, I hope you will upgrade these when you get time too

And some words on the scrolling to 'complete' those models
Can't wait to see more..
Lance