Just curious, have you thought about Powder Coating them? Not sure if they can mix that colour. Powder coating is stronger which obviously means longer lasting. Just throwing an idea out there. Not even sure it's possible (powder coating that colour).
I would definitely try to get them powdercoated. It will stay on a lot better, esp. when putting on the ( unbelievable tight ) stainless rings... I build trikes and sidecars for a living and we powdercoat all wheels silver with clearcoat powder. I`ve matched it with my ralleys and the color is practically the same. ( although it looks to be the org. paint on them, I `m not 100% sure...) even if the color is a little off, I would still go for powder.
The color on your wheels is what we used to use some years ago, but it`s more gray than silver. there are great colors available in powder, just take your time and find a company that uses the right color for you. ( or is willing to order..)