My guess would be a primary coat of something like shadow grey or even simple chaos black, then build up on the raised panels with fortress grey. The problem is that your average leman russ is a lot less streamlined then a thunderbolt. You'll have a whole lot more rivets and such to deal with even without side sponsons on the tank. It looks like the grey has been blended with a brown on the areas where it's out of the streamline, i suppose you could use a similar technique to represent grime on your vehicles.
I would say that the blue looks like enchanted blue but i'm not certain, again i'd build that up from black to get the depth.
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