Draigoch has more and more incoming damage debuffs as the fight goes on ...
You could get huge numbers there with heartseeker too.
Rotation: Swift Bow, Blood Arrow, Barbed Arrow (this bleed is nice, even more so when traited and legacied), Penetrating Shot, Quick Shot, PS, QS, PS, repeat.
Blood A's cooldown is your marker for Barbed A's bleed ending.
Alternating focus builders and focus spenders (all Fast skills) in this way cuts off the post-attack delay of the induction builders.
You should have plenty of focus if you have the right traits and are in Precision. If you ever run out, throw in another QS.
[size=1][i]A spaceship from another star / They ask me where all the people are
I tell them I'm the only one / There was a war, but I must have won[/i][/size]