Since the video i looted 2 ancient Serpent Sparkers which I equiped on characters #3 and #4... I'll try GR 50 later, with the DPS boost from the ancient sparkers I might make it.

http://eu.battle.net/d3/en/profile/c.../hero/31711726
http://eu.battle.net/d3/en/profile/L.../hero/23069299
http://eu.battle.net/d3/en/profile/F.../hero/23438644
http://eu.battle.net/d3/en/profile/E.../hero/36279264

Character #1 is the guy spamming Slow Time bubbles. The others are Tal Rasha dps.