Sub stats: ATK/Critical Mutiplier/Weak Point; If u want to use it in Void Interceptions then colossus, if not well there's not much stats to choose, u can use some element instead.
Bullet Intergration only deals about 4% higher damage than Target Detection, so if u don't have intergration yet or u find it costs too much capacity then just use target detection. DON'T use concentration priority, reload speed is VITAL to Wave of Light, there's no circumstances that u will only fire 1 magazine round, Pay-out won't save this cause the passive of this weapon won't last that long. With a fire rate, in continuous fire, a magazine could last just the passive's duration.
Wave of Light is mainly used for dealing Elite enemies and bosses. Be sure its clip is always not full, and when u need it, start reload and begin the shoots. 1 or 2 clips is enough for Elites in 400% inflitration.
As for Special Sight, well, Real-life Fighter do have higher damage bonus but it requires stack up, and that cost both time and ammo. And Impact rounds aren't so sufficient, u might need several rounds of ammo pickup if u want to deal with 2 bosses in 400% using this weapon only. As I said, it's more suitable for Elites u encounter on your way and those annoying balls bosses spawn.
I'm not sure Greg and Wave of Light, which one is better for a damage burst after colossus been brought down. But I'm pretty sure this weapon could deal quite a mount of damage and without those graphic-killing visual effects(lol). Since it seems we won't have another new scout rifle recently, and the frostwatcher sucks, blue beetle is more like a buff tool despite its above average stats. Wave of Light is the best scout rifle for damage dealing now, that I'm certain. I'm pretty sure it‘s worth your investment.