My 2012 F150, Ive noticed some of the underside bed rails have a good amount of surface rust, no through rust but it looks as though Ford didnt coat it good from the factory. My job hotshotting supplies takes me through alot of muddy limestone parking lots, saltwater etc and I hose off my truck regularly but would still like to prevent this rust from getting worse. Would Cosmoline RP 342 or Fluid Film be better for this?