IMHO, I wouldn't spray POR15 unless you have some serious safety equipment. POR15 is very unhealthy to breath. If you spray via a gun, the paint molecules could linger in the air long after you are done. If you don't have a pro spray booth that vents away the lingering air, you could risk future illness. Keep it in liquid form and just paint it on. It's worked well for me. Besides POR15 doesn't like UV light and will change shade. I'm currently in the same phase as you. I have my bumper, skid plate and hitch plus underneath scraping off rust and preparing to paint POR15. Once I have that done, I will rattle spray parts like the bumper with bed liner rhino type stuff. It will give it a more rugged look and protect the por15 from UV.