Max damage per hit as an evil cleric?

[Czardonyx]

So, I'm the GM of a Curse of the Crimson Throne game, and I've made Laori Vaus go along with the PCs both to help and to unnerve. And, she's probs gonna betray them at some point. But, that aside, I more-or-less rebuilt her sheet, and she is currently a level 8 cleric with the darkness and destruction domains.
She still has her +1 Spell Storing spiked chain, and she currently keeps Inflict Critical Wounds in it at all times. I gave her Vital Strike and Channel Smite as feats to further boost the Destructive Smite she gets, but I am still always looking for ways to increase her damage output. So, I wanted to ask:
Assuming that she keeps several "True Strike" potions ready at all times, do you think that adding rogue levels would be a good investment to increase damage? And if not, what?
Also, keep in mind that this is all for sheer damage. Thanks!

[Endoralis]

Save that you cant have True Strike Potions I dont ever think having levels of Rogue would help for that. I would instead put forth two levels of Barbarian and if high enough level get Improved Vital Strike and Furious Finish. Other such ideas are 5 levels of Inquisitor for Wis Synergy (Bane and Judgement Aint Bad) or Perhaps Abyssal Bloodrager.

[Claxon]

Rogue would be a terrible choice.

Without a flanking buddy to help her when she betrays the party it wont do much good to have sneak attack.

True strike, also isn't really a good option. It gives you a single basically guaranteed hit, but it requires you take out the potion as a move action and drink it as a standard action. Unless she basically has it in hand all the time, which would still leave it as a standard action to drink.

Also, Endoralis brings up a good point. You can't have potions made of personal spells, which includes true strike.

For the purposes of maximizing your damage...get her to as high a level cleric as possible to where she can cast planar ally and then have her cast it multiple times and let her minions kill the party.

Clerics themselves just aren't great at fighting, at least not compared to most other classes. They're a 3/4 BAB class with not much ability to buff themselves (except as standard action spells) that doesn't get bonus feats to really help them be good at fighting and have a less than stellar weapon selection.

They're back up melee fighters at best. Stick with summoning in evil creatures to do your bidding.

[Claxon]

However, if you are set on optimizing the cleric have a look at the various clerical optimization guides on this webpage.