So, I was looking at it, and just looking at the numbers and the number of GCDs it takes.

It takes 32 GCDs using a VerAoE + Impact and does 5440 potency to each target to reach 104 Black/White Mana. At 24 GCDs the potency would be 4080.

It takes 24 GCDs using VerAoE + VerSlow and does 5160 potency to one target and 1440 potency to all others to reach 108 Black/White Mana.

You could also change up and do one Impact rotation in there, which would give you 103 Black/White Mana at GCD 24, changing your damage to 4980 single and 1880 for others.

So for a straight up lots of little mobs, I would probably say VerAoE+Impact would be the way to go. If there is one large mob in there, it would probably quicken the fight to have your Melee Combo ready 8 GCDs sooner.

Would also have to take in to account how long AoE packs take to kill and how much mana you want for the start of the next fight. I dunno??