I spray with about 30 pounds of air pressure. My thinning is windshield wiper fluid that I got at Safeway. I usually thin at about 25 percent, but that would depend on your spray equipment. I do use a water trap on my air line. The clear coat can be applied with a flat finish. I used Varathane from the Home Depot and it comes with different levels of finish so make sure that you buy the right can. You will need to let the Latex dry for at least a week in warm temps before clear coating. Good Luck, Dave