I think light phosphate gray would be better, if you have to paint it. A better alternative might be to actually 'phosphate' it;.. Check out Palmetto Enterprises for their phosphate solution. Besides the solution, I had to purchase some Stainless steel pots (large enough for the parts you intend to phosphate), and a hot plate and thermometer.. (and lots of WD40 for neutralizing after the coating process).. It works great for the fasteners after you've cleaned and derusted them..
"Metal Rescue', or 'Evaporust'' works good for removing rust (non-destructively for everything else like paint, rubber, etc)...
PS. I remember fondly when my wife used to help me in the garage..