Sadly I don't have the file anymore; but I will say the majority of the work I ended up doing was via savegame editing from what I remember - I wiped all the buildings, infrastructure, etc and manually did those using console and instant construction cheat; I adjusted the tech of every nation to what I thought made sense with their level of development, I adjusted manpower levels after the first two test runs because they were far too high, etc.
The main changes I remember making to the mod itself were making factories more expensive [to prevent spam] and cutting out certain focus tree elements that didn't fit the way I wanted war declarations to play out. There was a lot of trial and error while playing to fix various annoyances though, both with game balance flaws and AI diplomacy misbehavior. It all depends how specific you want things to go though; I already had the frame of this story planned out (minus the results; I adapted to how the war played out) so I had to make sure things didn't get too crazy.
) put me onto it when I asked him for HOI4 AAR recommendations (I’m just learning the game, coming from a long-time HOI3 background).