Sun Shafts and 2 cameras

This Wiki is a bit tuff to navigate so this may be answered but I couldn't find it. 

First my sun shafts are crazy at all times, night or day. Is there a setting for that?

Also I heard there was some help in setting up 2 cameras, one for the long distance while the other for close, to help frame rate, yet I can't find a thing on it. 

Also is there a way for me to change from 6 pm to say 12pm on the fly? I know about speeding time up, but can time change be instant?