Don't use absorb health if max DPS is your goal. You have more effective ways to heal (surge, healers, maybe twilight, etc).

Also, don't run the same enchant on both bars. They'll share a cooldown and lower your damage.

If you're running Ilambris it's a good idea to use the opposite damage element (flame enchant on lightning staff) just to create more opportunities for the fire proc. It's kinda a good idea even if you're not, to apply the burning status effect. Put that on the front bar where you heavy attack and/or force pulse weave.

On the back bar, you can put a spell damage enchant or a shock enchant. Shock will give you more single target burst and the damage buff enchantment will give you better AOE damage.