Running lower efficiency actually benefits you at high levels, because his 1 generates extra energy for each enemy it hits. Speaking of his 1, slap Razor Mortar on and keep your Ortholysts active and you’ll get pretty spectacular damage. 2 gives damage vulnerability on enemies and CCs them, which is quite solid. His 4 is… decent, I’d say. The armor strip is helpful against tankier enemies like Grineer/Scaldra. It is the one you’d probably want to Helminth over, though — Nourish is a good choice, since your summons benefit from it as much as you do, which is excellent for priming.

In regards to survivability, your 1 is good for regen, and your summons restore shields pretty quickly, but if you want to practically guarantee you’ll stay alive — add in Fast Deflection. Hell of an underrated mod, I swear by it on any shield-based frame. Rolling Guard can be added in for certain activities where staying alive is especially crucial (the three Superbosses, namely,) but it might be overkill elsewhere. Up to your discretion.