My humidity was always around 50 and I just used HPS for the whole life of the plants, so I don't know about the blue light (do you mean MH) or humidity, but the contraceptives I'm pretty sure is BS. Why go through the trouble anyway? Just lower your temps for the first 3 weeks of their life. With lower temps I get more females. And not just with these seeds, either. With any seeds I try.

Plus saves you money, you don't have to buy those feminized seeds anymore.