Toot - When I sprayed the cars, I used Floquil "mud" which is fairly close to a buff color. Black chalk was applied using a stiff bruch to give the appearance if soot running down from the roof. The air brush was set to a fairly small volume and the air brush was passed along quickly at about a 30 degree up angle. A final coat of Dull Coat was applied when this was finished. I took no measures to protect the wheels. I was a novice with an air brush and didn't have a clue what I was doing. It sounded like a good idea, so that what I did. Passed that class in the school of hard knocks.