Terrify optional over 1 or 3, depending if you also want to shoot incarnon weapons like felarx/laetum/[Phenmor].
Use a secondary with multiple augur mods to allow shield [Regen]. Three augur mods in total allows terrify to generate 62 shields (which gives about 1.3s shield gate with [Catalyzing Shields] on).
If running longer missions, can use Molt Augmented, swap Corrosive Projection for Brief Respite. Umbral Intensify optional for Primed Flow if you have archon shards to hit 167% strength.
Stretch/[Augur Reach] is flexible for [Primed Flow].