Give full light, and adjust with ratchet straps to find the sweet spot. dimmers are a nice option, but id you have vertical mobility and space, moving the lamp is far easier then changing integral, factory settings👍. As for environment, Northern Lights usually has a very high resistance and range it can handle. That being said, the ballpark figures we look for bloom are 20-25 day temp (try not to exceed 26 as this may start causing transpiration issues). In a perfect world RH should be held at 55% or lower (down to the 30's) in bloom to avoid any standing water, fungi or pathogen development.
What's crucial is keeping your RH and Temperature in balance w/ one another. A drop in one will cause I rise in the other or visa versa (most of the time). A standard VPD chart will help you find optimal temp/RH ranges that our plants will acclimate well too and then we try our best to tailor the environment to those specs/benchmarks.
Lastly, circulation. If we can't quite control heat or humidity the way we'd like, adding more circulation allows for constant air movement, stopping possible pathogens and standing water from settling and affecting our plants. Plants are sweating? Add more air flow and all should be well.
Cheers and happy trails👍👌