I have a 12ft dump trailer that I use for work and hauling the quad.the sides are getting pretty rusty and need taking care of. Bottom is still in great shape Cuz I have sparayed it with fluid film from day one. So I was gonna use chassis saver or por 15 but didn’t like the idea of having to spend $100+ and still have to put a top coat on for UV protection. So I found some rustoleum professional at home depot gloss black. Directions are similar to the chassis saver knock off rust and apply ( I did this today). They recommend using a primer to and I am rustoleum heavy metal. So has anyone used this stuff before? I’m going to be doing it all with a brush per the directions. I bought the best brush I could get for oil based paint. Any tricks to keep the brush marks out or tips, this is my first big painting project.