Hey Nick! The weathering I do is to use dirty black thinner to dob around some bolts, edges, etc., and after all the painted marking are on, I use a spray can of that camo light tan from Walmart. I just dust the tank from a distance especially low down. I paint the U.S. tanks tracks the same color of the tank, no primer. and let them wear off the high areas. I'd like to show a picture of my Shermans but it'll be overcase and rain the next few days... I'll try to take a picture tomorrow under the garage lights.
Mike