If you can find someone to make you Thistle Tea, vers is your best bet. Duels are over fast (Unless you're up against a priest/lock you're going to always lose) so the vers will give you big damage and make you tankier, and while haste would normally give you more attacks, just drinking the thistle tea after you've popper your 2 mutilates means you get another 2 free ones. That will probably kill anything unless they pop an AGM, at which point EF will stop proccing until it's off and it goes back to a full PPM start for EF at the end, making a vers burst on two mutis still the strongest and likely enought to gib them.
I'm half asleep so the above paragraph might be ranty and not fleshed out or make any sense.