I have been trying out axial lighting for my proof coins and it worked out quite nice. Here is an example. Have any of you tried it?
I played around with it, but the setup was bit much for me. Here is one of my test shots from awhile ago. Good luck.
I haven't tried it, but I'm always open to new photo ideas and your pic looks great. Can you describe your setup ? Perhaps photos of the setup ?
Attached is a link that describes an easy setup. It works well for any nickel coin also. It eliminates that typical "blackish" look. I use a cold or bright white lamp for the silver proofs and warm white or broad spectrum for copper, brass and bronze proofs. http://www.sigma-2.com/camerajim/cjgcoins.htm
Axial lighting caught my fancy several years back so I built one. Then found out I had no need for it since I had no proof or proof-like coins. D'oh! So it sits off to one side unused.