Deadeye Spiral + Sniper is viable for Citadels?

Hi there!
Im looking for a full DEX ranger build (deadeye), or not requiring big amounts of int/str.. Tried lightning arrow, sweet, but now im using spiral for clearing, and is completely wonderful.
My problem is about citadel bosses.. Sniper with frenzy charges is many times hard to make it work against citadel bosses, because they hit too hard..

Do you have builds using these skills passing citadels?
Thanks!