A question about Seleucid economy

[Lysandros]

AND! Only use a few Allied generals or governours in Type IV Govermnet. They drain your money like crazy.

Actually I can strongly recommend using them as governors. In my last Seleucid game which I played under the impression of a Sweboz and a Romani game when I had tons of money in either one, I wanted to find out exactly why it had always been so difficult to become rich as a Seleucid player. Corruption is only a minor reason as you can see in Marcus' financial summary, but upkeep costs for the army are insanely high. So what I did in my last game was installing Type 4-governors in about half of the provinces. I chose those provinces where foreign barracks allowed for much more units than the factional barracks (including Ekbatana and Susa for example, where I switched back to type 1-governments later for the cataphracts). The governors can also replace much of the usual garrison you keep in the provinces far away from the centre of the empire.
It really makes a huge difference if you recruit only as much units as you really need! A type 4 governor himself gets

Effect Influence 5
Effect Law 4
Effect Defence 1

in any case, so he will easily both eliminate corruption and keep a city content even if he is your only garrison. Furthermore, his bodyguard with its great number and his ability to get traits and ancillaries will make him valuable not only as an administrator but as a military force, too.