Rotscale

Hey I know everyone is going hectic trying to find the best Rotscale build, but I was wondering, maybe you could have 2 domination mesmers with e surge and other energy draining spells, but most importantly 2 arcane echo blackouts. I understand the hex wear off faster but two blackouts and the recharge time should be enough fo the next mesmers blackout to recharge.
What do you think, will this work well??

A warrior can tank him alone indefinitely, but he can't do enough damage to counter his regen. So you'd need some damage dealers, and a monk to keep the damage dealers alive. But I think you could do it with 4 people, maybe 3.

An effective way of doing damage to him is using his massive health against him - Grenth's Balance.

Your blackout build - I think possible one mesmer with Diversion could do the same job better?