I have some ideas about how to do swarming with these songs, but have yet to try them out.
One is to try the 74 song on the Mammoths in Icefall glacier because they are normally indifferent. So I can HoS them from a distance and then fade immediately, run up and charm, swarm... if the charm drops early, just fade and repeat. If they are almost dead when the charm wears off or canceled (via invis), DoT them down as in any other swarm kiting.
This takes a lot more mana because of the use of fade.
I'd be interested in other techniques to charm KoS mobs, given the 30 distance issue. I've thought about mezzing, running up, HoS, then charm.. etc.
Other ideas?