Been thinking for a while that I wanted to do a generator build for DH. So I decided to try Bola, considering it was basically the only generator (not HA) with supporting pieces of gear with potential to do decent damage.
I started my build with Balefire Caster + Dawn while cubing the Emimei's Duffel. I could not for the life of me get a decently rolled Dawn, I either got good CDR on the affix, or Disc. I barely completed 75. So I decided to run Leonine + Duffel while cubing Dawn. With a 80% Ess on Follower and Leonine, it felt like I had a Monk pulling everything in. Was able to clear GR 80 within 3 attempts.
Large open maps are very much preferred, though I had some good attempts in Keeps. Spider caves were not kind to me, all the small holes breaks up the mobs too much. Best map is Arreat Crater type imo.
Playstyle is very dependent on grouping mobs correctly and firing into the groups of mobs, hitting the stragglers following you is a one way ticket to going over the timer. Area Damage is super strong with how the build plays.
I think with a better weapon, I can do 83-84 with a bit of fishing. With much better gear/gems/paragon, something like 86-87 might be possible.
Here is the exact gear I had completing 80. 1225 Paragon, 68 SS, 88 Zei, 91 Trapped. ~70-80 augments on most ancients. Forgot to augment weapon.