Brian,
My suggestions for Light cache are:
Vray Settings:
Dynamic Memory Limit: 2000+ depending on how much ram you have, but higher numbers do make a big difference when using proxies
Default Geometry: Static. , proxies and displacement use dynamic but I have found that using static make a huge difference in speed.
If you have many lights reduce the Light Cache subdivisions under 500
Guillermo Leal.
http://www.evvisual.com