Caliber-based damage variation for different creatures?

[LX6R]

I tried several of the damage overhaul mods on the nexus, and none can really fulfill my idea of how damage should work. Thought I'd post about it here and maybe with some help I can make it myself (or maybe someone else if it's too complicated for a noob like me).

 

What I basically want is this:

 

NPCs levelling with the player

Caliber-based headshot damage

helmet protection

Dismemberment

 

Better locational damage seemed like a good idea at first, but the mod is a feature creep. Looking at the description I feel forced to change aspects of my game in the way the author wants on top of the changes I expected from the mod.