Right Macro Equipment...

I am getting ready to do a jewelry gig and I was trying to decide what equipment will produce the best results.

I am shooting with a 40D and 580EXII. I want to pick up a 50mm 2.8 Macro as well as the Canon MR-14EX. I guess my biggest concern with the ring light is whether or not ANY shadows will be cast behind on my white seamless backdrop. And if so, could I combine the ring light with my 580EXII to get rid of the shadows? Would I be better off just using a 430EX as a secondary light and then my 580EXII as my key?

Any advice on this would be much appreciated. Thanks!!!

I think jewelery specialists normally use a light box which you can light from below, a constant light source of two lamps and one below may be the way to go. A Translucent storage box like Daytona uses for his Rolex photography seems a good idea.