Recommended Archon Shards: 2x Max Energy (can also swap them for whatever if you go for [Primed Flow] over [Augur Reach]), 2x Casting Speed, 1x Energy Orb Efficiency

Recommended Focus School: Zenurik (energy [Regen] combos well with nourish)

Aura: Both Enemy Radar and Energy Siphon work well for your aura slot, without having to use a forma on it.

Helminth: Nourish is here to free up mod slots for efficiency and/or an arcane slot for energize. It also affects your Accuse allies.

DURATION: [Xaku] doesn't really care about the lower duration, because of the vast untime pausing his other ability durations. It even has a benefit of forcing you to cast vast untime more often to apply it's slow and void damage vulnerability.
EFFICIENCY: Nourish has us covered so we don't have to bother with it.
RANGE: You want all the range so you can have more guns with Grasp of [Lohk].
STRENGTH: You want enough for full strip with [Gaze], but The Relentless Lost makes this too easy, so I slapped a bit more to boost all the other abilities.