FWIW, it should be the corals you are keeping or planning on keeping that determines light intensity and spectrum. Also, once setting are decided they shouldn't be changed without due deliberation, everytime lighting period, intensity or spectrum is changed it's forcing corals to adjust their photobiology, the extent of the stress cause will vary and some corals won't care but some may also have a hard time adjusting.
When I set up my 197g (48x38x25). I'll eventually get 2x Photon V2 Pro 48". I can't imagine I'll keep the intensity of two of these above 30%. That being said, 30% is just an educated guess......
Settings will most likely be different for each persons tank. I run 2 photon 32s over my 36x24x24 sps tank. I run white red and green at 5% blues at 35% with a 45% peak.