Build based around using his full kit while trying to be in Meatball as much as possible.
Aura can be whatever you want.
[Primed Continuity] for keeping buffs going.
[Primed Flow] and [Rage] (along with buffed Nourish) should keep your energy up.
[Umbral Vitality] and [Umbral Intensify] are really all you need since having 5 mobs in your belly should give you more than enough armor.
[Stretch] and [Augur Reach] since everything in his kit benefits from range.
[Adaptation] to really stack up the tanking.
Catapult in exilus since it's worth using Pulverize now.
Molt Augmented is one of my general "go-to" Arcanes. Arcane Grace will give huge amounts of survivability between stacked up [Adaptation] and a full belly.