I really ask me if I should use lords unique ressources too, that tend to be low on start and high on late game. Like on essences for Ostankya, -25 per turn seems fine on start but is negligable on late when you have multiple armies.

For now I did something like that, but I will greatly appreciate any advice of ostankya players about that.

Ostankya
Spirit Essence -36 per turn
Chaos Undivided corruption +5

The chaos undivided corruption should also remove a part of essences gain through the lands if you don't adress it, and can become a factionwide issue. So should I keep "Spirit Essence -36 per turn" or do you think it's better to stick on global ressources like winds of magic for exemple.

Edit:
I could take a look to do it per regions, that should scale a bit better between the start and late game.

Concerning Ostankya I opted for a penalty of -5 spirit essences per province per turn.
So with 20 provinces, you have a penalty of -100 spirit essences per turn (for 5 turn), I will probably do a proper campaign with Ostankya soon but if you have played it, is that seems fair to you.
How many spirit essences do you make per turn at this stage of the game ?