Looks great. Takes me back to the days of building plastic models, and the extensive weathering I used to apply. I used chalks, tempera paints, anything that provided the perfect shade and texture I was looking for. I finished the weathering with a final clear, flat, (or gloss, depending on the subject), coat to even out the layers and provide a protective layer. By the way, whose A-10 is this you are working on?
Jesse