I originally kept a 1:2 group but the females were constantly harassed and ended up being stressed to death. The lone male was in my tank for a few months after that and during that time span went completely nuts. Maybe it was just him but I'd say generally people recommend keeping them in groups since they are social...just make sure you get as many females per one male as possible.
What other fish are you keeping it with? You can keep female Swords or male/female Platy, probably Guppy too. They are social fish, so they like to have similar fish to swim with and annoy.
my plan is to add the one swordtail to my 7 nenon tetras and 4 creamsicl mollies. then add 5 scissortail rasboras, 5 silver-tip tetras, 4 longskirt black tetras and 3 lyretail guppies to the mix.
I have one male swordtail in my 38G. Thinking of getting another one or something. He gets a long fine with everyone but he just wants to do "the dirty" with everyone else.
I would choose your favorite three species of the fish you mentioned. My suggestion would be mollies, swordtailes and some type of small schooling fish.