Painting radiator covers - how to match color and what tools to use

I have a 20 year old house. Heating system is hydronic with metal baseboards all over the house. All are the same color and design, a kind of pale ivory (not powder coated from what I can tell). Situation is a follows: many of the radiator covers are dinged from normal use and 4 are severely corroded from dog and other mammals urine. What I want to do is recondition the 4 badly damaged ones and touch up the others. The backboards cannot be removed so they need to be refinished on site. The covers and end-caps can be worked in the shop. My problem: There is no equivalent color match in spray paint. Not Krylon, not Rustoleum, not Vaspar. If I want to do touch up, I need the color to more or less match. My questions: How to proceed? What tools should I use? Low pressure spray system? How do I match the color? What kind of paint should I use? I know I can easily buy latex and get it color matched at HD or something equivalent but will that work on metal? Should I go with finer tools such as Testor air brush system?