There are two information pages under "Advanced DIVA for Rhino Concepts" on the sidebar to the right. Beyond that, there are two videos and presentations on our DIVA Day 2012 page you might find interesting.
> To effectively run a thermal model, are these values required?
DIVA will warn you if climate-based shading/lighting results do not exist before running a thermal simulation. If they don't exist, default lighting levels (11 W/m2, always on -- I think) will be used.