I suggest using:
4 Amber Archon Shards with ability casting speed (to spam 2 and 4 faster) (only 2 standard shards to gain the same as the [Natural Talent] mod, matching mods such as [Primed Continuity], [Primed Flow]. It would take +4 standard shards to compare, it would even take 3 normal shards to pass a mod like [Augur Message]).
1 Amber Archon Shard with energy orb pickup boost. (If using [Exothermic], if else 1 Crimson Amber Archon Shard with ability duration would be neat for burn time.

1. Cast 1.
2. Cast 2.
3. Cast 3 (the wave have to hit the desired enemies before being cast again).
4. Spam 4.

[Exothermic] is an option. You could also use [Adaptation] (forma [Stretch] and you can fit anything in the [Exothermic] slot)

Gloom for lifesteal and a bit of range for Gloom. No health mods are needed because of Immolation and [Adaptation].
(Some people suggest Pillage, but it would have to be casted 2 times to fully armor strip enemies, but 3 can also do that in 2 casts, yet that ability has 3x the range and is much faster to cast. the only nice thing about Pillage is the shield regain, but I honestly Believe the Gloom 9% slowdown is way more beneficial in general (same goes for, except that ability covers 2/3 of 3)

If you get the 250 kills with Molt Augmented, Gloom will slow enemies down by a huge 95%!

Energize for energy supply, so we don't need the augment.

FOCUS SCHOOL:
Madurai for casting speed

Enjoy!

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