PPG makes a sealer, DP series and it comes in several different colors, black white, red, green. It is a very good epoxy sealer and sticks to about everything and holds up. I painted a duck hunting boat with it over 10 years ago right over scuffed aluminum and it is still there. It's been out side since the day it was painted. the dull satin finish may be what your looking for. Great for a Rat Rod. It would cut cost too by being a one stage paint job. It is user friendly too. If you put any wax or polish flat paints, they gain gloss, so you want a wash and go finish.