I think one of the most important things is coverage. I sometimes spray, but before I spray I use a brush and paint around nuts,bolts,rivets, and places spray can't get to.
Use what you want, but I have yet to see someone post the outcome after 20 years when they used a high dollar paint such as POR 15.
I have no thoughts against that type of paint except for the cost.
Back in the 70's I painted the frame and suspension of one of my cars with 2 coats red primer, and 2 coats enamel.
I was using Rustoleum and that paint is still on the frame.
I recently primed a frame with Chassis Saver and covered that with Rusto Black Satin. I expect it to go the distance, but I'll have to wait about 15 years to know for sure.
Dan
