Help to change unit/city artstyles

[seasnake]

So I made a mod to add Portugal as a playable Civ. It works well, but before publishing I wanted to create an Iberian City and Unit style to add some flavor. I've tried to do it based on Civ 4 mods that did the same, but no luck so far. Has anyone been able to do anything like that so far in Colonization?