Weapon proficiency for Berk/T dual

Did some googling, not much turned up other than Celestial Fury and Staff of the Ram. That's a problem because I'm not planning to do much backstabbing.

So.. best weapon for a B/T dual? I am doing a duo run (Berk/Mage and Berk/T) and Staff of the Magi and FoA/DoE will be going to Berk/Mage. My Berk/T will be focusing on traps, pickpockets, locks etc. Of course he will scout too etc but not many backstabs. I will put Staff of the Ram on him in case, but..

Anyways. Keep UAI in mind. I was thinking maybe Carsomyr or dual wield Foebane and Purifier. Or whatever.

Thanks