It might also make sense to do it in the other order, Progenitor first, then Halcyon. Those are definitely the Advent's two most useful caps. After that, perhaps another Halcyon or Progenitor, then maybe a Rapture. If you need to disable a Level 6 Marza to interrupt Missile Barrage, then you need a Radiance (Detonate Antimatter) or a Revelation (Reverie).
