Changes to Def files not working

So, because I can't help myself, I made some adjustments to the GlobalDefs and ShipComponentDefs in the following path:

C:\Program Files\Epic Games\GalacticCiv4Supernova\Data\Gameplay

Nothing drastic, I changed GlobalDefs to Turn Limit 0 and also set the diplomacy cool downs to 0.

I changed ShipComponentDefs to remove the 1 per ship limits on the Transport Module and the 2 Carrier Modules.

These didn't stick.

My first question is:  IS the game even in a place right now where modifying DEF files will adjust gameplay, or is everything still basically hard-coded?

Second question is:  Where do I need to make those changes, since there are multiple locations for DEF files at this point?