[AzRed]

B4B and Hawks Eye should be used together, every barrage will fall into the window of both of those if you hold b4b/HE for a few seconds to let them line up. Even better is actually holding an emperyal arrow and having it do something like:
(some GCD) HE+B4B > Feint > Barrage + Arrow > Iron Jaws ........... Feint > Arrow > Iron Jaws (HE/B4B drop off here)

Reason doesnt matter for Barrage + arrow is barrage eliminates the possiblity from crits on the skill its buffing.

Flaming Arrow and IR though should always be used in conjunction.