[Cohen]

With Pythium I prefer go first Thau 5 for Soul Slaying.
Light of the Northern Star isn't so useful for Pythium as for other nations like Abysya, because Pyth has commies that in early game does pretty well, second, far better to use the Banner, you avoid fatigue and continual gem expenditure.

Quills are Const-2, yes, lanterns are Const-6, true.
But the 5 air gems I spend in the Quills could be used in more better ways. Yes if I take Drain-3 I could think on quills, but I doubt I'd take Drain scale anymore unless is mandatory by race or game settings.

With 5 Air Gems I can do cloud trapezes or a call of the wind (useful to try to grab an enemy province or to see exactly what an enemy army has inside and which spells are scripter in first one or two rounds), and if I mass gems I could do far more (mass seeking arrows, storm staves and helmets and so on).