Graininess In Photo

Lustrous silver has always been most difficult for me, as well. Generally speaking, I achieve my best results by slightly underexposing the shot, using a narrow (high numerically) aperture. Paradoxically, contrast also improves with faster exposures. In most cases, though, I end up postprocessing to get the desired result.

Use a single light instead of two and see where you are. One other possibility, depending on your degree of control over the environment in which you're shooting, is a lens hood; you could be bouncing light into the lens from adjacent surfaces, and that will reduce contrast.