And i do not really know how do i have to integrate the lights into my lamps.
I have used two spotlights with very large cone angle. Is there a better way to do this?
You can use a FGmax 2500 and a little Blur on FG tab (4-8). See what works best for you. If you add more blur you can lower your FG max (but your indirect shadows will be a bit blured).
hmm spots with large cone are not a good idea, especialy when you use "spot to arealight" in Kray.
Also might want to check the photon number multiplier on the motion options for the lights, since using lot of "artificial" lightning, you may have huge problems with photon sharing and getting light leaks / bad GI calculation...