I am one of that crazy people who is leveling and gearing up this unit. Currently, i have him in G.X, 6 starts with: 22925 heal 48627 protection 103 speed 44 potency 41 tenacity 31,7 armor 24...
I use crit avoidance arrow and as much protection and tenacity every where I can. Also use all tenacity mods to try and keep daze and buff immunity off him. Seems to work pretty well.