I suggest using:
3 Azure Archon Shards with Energy Max, since [Harrow Prime] has low base energy. (You might want to swap [Primed Flow] for something else (however this will make energy it a bit tedious to work with, you will have to use Wellspring from time to time or rely on weapons too from my testing (especially if there is only a low amount of enemies left)
2 Amber Archon Shards with ability casting speed (if you don't have that, you might want to swap [Streamline] for [Natural Talent]).

ABILITIES:
Thermal Sunder (if no Thermal Sunder then swap [Archon Vitality] for [Umbral Vitality] and [Overextended] for Umbral Intensify)

ARCANES:
Molt Efficiency since you get shields from Augur mods.

Focus School:
Zenurik for Wellspring/more energy over time.
Madurai for casting speed (might want to swap out one or two amber shards for more Energy Max)

Personally, I am going for [Primed Flow] and 3 Azure + 2 Amber shards AND [Primed Flow] because I am a bit lazy for Wellspring.

Enjoy!

Eidolon [Harrow]: Eidolon Harrow