Females are not needed. There are many who have all male show tanks where all males show color. The key is not to get more than one of the same type. In my 120 I have about 8 right now. I just took out a red emp who was monster size due to over aggression. It just depends on the fish. Also if you mix with females you cannot sell any of the fry since it is mixed groups.
I'm thinking 10 max, maybe more initially because I'll get some smaller ones to grow out, and keep the best of those. The peacocks I have now are all A grade.
I would do a minimum of 15-20 males only in the 3inch or less range. The bigger more colorful males will pick on the other ones growing up thus delaying them showing color. As they get to 4-5 inches thin the herd a little and see what you end up with. Heres a video of my 100G tank