The thing is, fighters being so intelligent, they have their own personalities. Therefore it cannot be said that "Yes, you can have this many females to this many males in this sized aquarium" because there may well be personality clashes. In one aquarium 1 male and 2 females could work but in another, that same combination may end in tears. I have owned male fighters that could easily have been kept with females, yet I wouldn't put my current PK with females unless I wanted to breed them. Even then I'd keep a close eye on them. It all comes down to the personality of the fish really.
Hope that clears it up