I was just thinking ,"What an improvement". As for the prep before paint,,,use XIM primer,It bonds to chrome,,then paint the centers gray. HRP
Cragar did have a wheel sold as GT's they were Aluminum polished on the rim and painted in the center as opposed to the fully Chrome plated SS. GT's were a less expensive and in my opinion less desirable look alike.Usually the SS wheels that I have seen with painted centers have flawed chrome and the paint appears to be there to covers the flaws in the chrome. I have a couple of sets of GT's,the ones that I have have a steel rim with an Aluminum insert pressed into the center. To me making your Cragar SS wheels look like GT's would be like have having an Shelby Mustang and modifying it to look like a typical fastback. I know it's a matter of taste but that is my two cents worth.