Like deathwing said, Sunwuko's 4-piece + daibo (preferably flying dragon) is the best. However, I disagree about using no generators. The damage potential of legendary gem procs is massive and WotHF: Fist of Fury is incredibly good at exploiting that since it adds a stackable DoT to all of the second stage hits. But aside from that, the skill has decent base damage values that can be ramped up very high with the right set up.
Using depth diggers (+100%), Simplicty Strength gem (+37.5% @ rank 25), Belt Affix (+15%), and BP? Affix (+15%), not to mention multiple +holy items, you can dish out heaps of rape using a generator WITHOUT giving up the ability to spam bells non-stop. When my epiphany is on cooldown I can spam click my mantra without running out of spirit by using the air ally active once before epiphany is up again. I regularly finish lvl 27-28 grifts with 6-7 minutes left
with this setupand I am sure I can go higher but I have been focusing on upgrading gems (I currently have three that are rank 25, and one that is rank 13) so I normally just cash out on the first grift after my trial. Flying Dragon turns me into a buzzsaw of rape and mayhem that is extremely hard to kill because I practically never not have my mantra of healing shield up. And I kill rift guardians incredibly fast.