It really depends on how strong your lights are, but 8-12 hours is pretty much the standard. I run T5's and leave the daylights on for 10, and the actinics on for 12.
As far as the moons, I try to mimic the lunar cycle, best I can. 1 week off, 2 weeks increasing in time, and 1 week on most of the night. I'm sure it's not necessary, but I think it gives everything a more natural feel. Most spawning is governed by the lunar cycle, corals included, so...why not? Still hoping for some of my corals to spawn!! Fingers crossed