Just play around with the mob density, radius and skill. (ie: cloud of bats with 5 radius & 7 min mob is not working for me, but dire bats with 15 radius & 4 min mob work wonders).
70 is very doable with with wd/wiz (95%+ success rate unless it wanders around) and i only have 12xx paragon and havent augement anything since the rolls is still far from perfect, it will took around 10-13 mins though so i still do lower grifts for efficiency.
so yeah with a 2xxx p, lv 80+ augments and perfect roll it can go much higher.
70 is very doable with with wd/wiz (95%+ success rate unless it wanders around) and i only have 12xx paragon and havent augement anything since the rolls is still far from perfect, it will took around 10-13 mins though so i still do lower grifts for efficiency.
so yeah with a 2xxx p, lv 80+ augments and perfect roll it can go much higher.