To be exact:
First the game reads the original big files, then it reads the custom bigs and then the files in Data and Art folder.
Example:
You have modified ChinaInfantry.INI and put it in the Data/INI/Object folder.
At game start the game reads first the original ChinaInfantry.INI, from INIZH.big!
Then the game reads your custom ChinaInfantry.INI file and overwrites the original ChinaInfantry.INI with your custom one!!
chears, and things look good im seeing basic changes iv made appear in the game like team colour options, start money options and my new faction is even there though its listed as MISSING: 'side:NewRegime' and when i play it it crashes.