Ah thanks Clervis for pointing that out, wasn't sure that it was since your calculations say that it accounts for conviction, but didn't know if it took in elemental resistances as well. In that case then yes, elemental synergies will always end up with more damage, but of course more life leech is always an important issue to consider.
Why not use vengence?? You already have the synergies mostly just pump salvation and holy shield even and your golden. Add a defiance merc with HF and no worries. At least thats what I think and im going to do. I hate zeal. I dont mind using potions all the time.
An avenger would require intensive gearing tho (and you're already bound to certain key RWs), but for immune back-up, it's really nice. Remember to max another Resist tho, since if you're using Dream and Resist Light, you'll want to use Vengeance for Light Immunes. (This is assuming OP has already weighed in Vengeance yet decided to main in Auras).
Oh, and Infinity + maxed Fanat would be nice I imagine