Total theorycraft, possibly bad.

Could be used in Index (hence Enemy Radar), or just as a general weapons-focused [Equinox]. Max duration for the [Duality] specter to stick around, some range and efficiency so [Maim] is still is usable. Mend is less helpful due to the low strength, which also means we can skip [Energy Transfer]. Can always Metamorphosis twice to get back to Day Form.

[Vigor] is a complete flex slot here; [Equilibrium], [Augur Accord], or others I haven't thought of.

Per the wiki, the specter shares an ammo pool, so consider a battery based weapon: [Fulmin] (Prime), [Flux Rifle], (Tenet) [Cycron], [Bubonico].