really depends on the look you are going for, there is no real "perfect" setting. Some maps look better with an orange color light and some with a slight blue one. Length should not be anything further than default imo, but you can widen it a bit. Just play around and see what looks good, thats one of the great things about mapping, not everything necessarily looks good being the same in every map. Experiment! Just be sure you disable dynamic light in the flag
I don't exactly know what the Const. Line. and quad. settings do. so generally what would you put those at? same with the focus. I want it to be strong.