Been doing this since release but one thing you should add is that apply every dot you can before you sleep the target as dots will keep ticking as the target sleeps.
Rinse and repeat but wake them up with a CS stone 2 and then fluid aura followed up by aero 2-> aero 1 *as aero 1 is instant and can be cast right after a spell, then sleep them again.
By then the group should be done with the other enemies. If they r close to killing the others i'll just aero it to wake it and make it walk back to me so the tank can grab it etc.
It's the beauty of the synergy of fluid aura and repose.
Also works well in pvp.