Unless you're -truly- in it for the challenge, and not the win/skin, just wait for the Command center overlap and use Lightblood Elixirs/Greater Blessed Bandages once you get comfortable.
As far as tactics, I concur with the majority: take MFD and the 6combo point talent and treat it as single target for the most part. The hard part will come right at the end when everything happens at once (usually under 10%, for me). Just stay calm, avoid boulders, and kill umbrals ASAP.