During Boss fights, I feel like as long as you..
1.Dont cap mp or blood.
2.Proc & use blood spiller as much as possible.
3.Only use Dark passenger for aggro or on 2+ enemies.
4.DA+ carve and spit, sole survivor, and plunge on cd.
5.Prioritze delirium to be used on Blood
weapon.
6.Avoid grit as much as possible.

Your dps should be good.
Is there anything im missing?
Pls share your thoughts.