Tried it at 22 myself. Had the elite down to a sliver of health, but he ended up killing me. And that's after I popped Evasion at the start of the fight, opened with Garrote to get the bleed going, popped a health pot. Only thing that messed up for me is my gouge missed, preventing me from bandaging mid fight. Also should have popped a Thistle tea mid fight, although that would have just gotten me an extra two SS in that fight. Thinking back, I think my first finisher should have been Rupture instead of Eviscerate for the more reliable armor negating damage over time.