Join Date: Apr 2011
If it's for large panels such as vehicles, you are going to have to aply several thin coats to get a good base color to begin with anyway. I doubt your primer will be that much of a factor. And edge highlighting should always be pretty fine.
You may want to consider a midstep along the mix to highlight that you didn't use on your infantry though. Big armorplates do require a different aproach somewhat to regular infantry (if you want smooth results that is). I have very little experience with these colors though, so that's not THAT much help. Maybe experiment first on a thin piece of plasticard with similar dimensions to the raider plates?
Remember that you can still work with multiple thin coats for highlighting for a smoother transition (if you feather them on) or with a final glaze that binds these colors together. I'd guess a brown-red type glaze looking at these colors.