The following is a repost of a thread that I created in "Endless Space 2 > General Discussions" on Steam (link to initial discussion) as Genghis Khannor. 

For the sake of simplicity, I have also included a summarized rendition below -- focusing on the main points, as well as the research and testing I have since concluded. Essentially, I am looking to introduce a way to increase the amount of ground troops viewed in battles. 

Initial Posting

• "The ground battles visual pacing has also been heavily tweaked; no more will you see two blobs of units against each other, now each ground battle tactic has its dedicated visual formation, unit types attack independently, and impacts are focused on units," (1.3.3, Supremacy Update).
  
• "Obviously we have moved well beyond this update, but I have long been left wondering if there is any method or mod capable of revamping the scale of the units shown... is there anyway to increase the amount of troops shown in ground battles?" 

1st Response/Lead 

Credit: The-Cat-o-Nine-Tales

• "I haven't had time to check through the files, but if you check the folder "steamapps/common/Endless Space 2/Public/GroundBattle" you may be able to find some values that alter the number of troops displayed per manpower spent and get the desired effect with a small mod."

Present State/What I Have Attempted  

• "I was looking through the recommended folder, but was unable/incapable of finding any specific values that clearly defined a correlation between manpower and the number of troops visually displayed. I ended up pouring over a few different files, including some in other locations such as the Schemas, Simulations, and Settings folders.
  
  Ultimately, I played around with editing and testing values such as:
  
  "SocleSize=_" -in- GroundBattleUnitConfigs + [Updates8&9]+[DLC1,2,&3] ; this appeared to change the size/circumference of circles on the ground surrounding troops.
  
  "VisualYPositionOffset='_" -in- GroundBattleUnitConfigs ; this does what it says it does, changing the location of the units as viewed on the grid.
  
  "CollisionX/ZRadius" -in- GroundBattleUnitConfigs ; uncertain as to the exact function, probably has to do with explosions and similar graphics.
  
  Searched for "Prefabs/Game/GroundBattle..." as included in the AnimatorOverrideControllerPath -in- GroundBattleUnitConfigs ; non conclusive
  
  "ManpowerGivenPerLair" -in- SimulationDescriptors ; this is a direct/literal value of the number of troops fielded by the pirates. I hoped I would find similar data elsewhere, but so far I have been unable to. Regardless, this does not apply to what I am attempting to remedy.
  
  "<Column Name='Manpower" -in- GuiElements[Tables] ; seems promising, needs further testing and confirmation. "Width='56" Is this what I have been looking for? Would increasing this change the number of displayed units?
  
  "<ExtendedGuiElement Name='PerformanceManpower" -in- GuiElements[EmpirePerformances] ; looked like this would be the source. Seems to hold RGB values/icon size, unfortunately not much else?
  
  "I'm rather new to this, but I think I've made progress... I am afforded limited free time and my prior searches on this have produced lacking results... For the future, I can provide the directories referenced... I only did it this way because I was using a copy of the files... Anyhow,
  Cheers!"

Special thanks to Groo the one, for recommending both the Amplitude Community Discord and these Dedicated Forums, The-Cat-o-Nine-Tales for a direction to strike out on, and Bozobub for the encouragement. I will be crossposting this submission across the general, game design, and modding forums; if you're interested in the fruits of my attempts, feel free to look at these, or simply view the original post on Steam for updates. Again, any and all help is appreciated.

-Thanks in advance 

Those will update the visual by giving more troops, but they may also have balance impact. Speaking for purely visual changes, it's not easy to change. (As mentioned in another thread, a gameplay programmer told me the "troops to visual pawns" ratio is apparently defined in the prefab.)

But thank you for pointing those values out. I knew I had seen something like that before, but could not remember where.

Eureka! I want to thank everyone, especially @PARAdoxiBLE:

PARAdoxiBLE wrote:

<Property Name="ManpowerCostReduction" BaseValue="1"/>

<Property Name="InfantryManpowerCost" BaseValue="5" MinValue="1"/>

<Property Name="TankManpowerCost" BaseValue="15" MinValue="1"/>

<Property Name="PlaneManpowerCost" BaseValue="20" MinValue="1"/>

Public/Simulation/SimulationDescriptors[Empire].xml

I briefly tested changing the BaseValues in a new game, and it did increase the amount of deployed troops -- capturing the quality I desired for the time being. I've since began working on my first mod, to supply myself and other individuals such as @jacob19831217 and @MasterofMobius, with a polished and easy-to-use adaptation. I have made a dent using the Endless Space 2 - User's Manual as a guide, but I've reached a point where I am unsure how to proceed and am hoping someone will be able to provide some clarity.  If someone has or knows of a mod that is similar to this one in the scope of what is attempting, that would be a perfect reference to build off of. I'm determined to see this all the way through, so here is what I have put together so far: GroundBattlesPlus - Copy.xml SimulationDescriptors[GroundBattlesPlus] - Copy.xml. 

Additional questions are: 

1. What type of simulation modifier is this? 

2. Where can I find the exact SimulationDescriptor Names and Types for this; are there any?  

3. What about the TargetProperty and Path? 

4. Am I correct in assuming that the operation called for editing the given values would be subtraction and addition respectively? 

5. Am I way off the mark here, please let me know if I'm doing any of this wrong.  

Anyways, thanks again to everyone for their help and I'm very pleased that we've already made this much progress in such a short time. 

1. What type of simulation modifier is this?

2. Where can I find the exact SimulationDescriptor Names and Types for this; are there any?

You should be able to define a new SimulationDescriptor for this, though you would probably also have to assign it to all major and minor factions for it to properly take effect. I think the the type depends on what your are applying it to and how you are implementing it. I haven't personally tried to make changes that affect everything, so others probably have more experience with this and can help you better.

3. What about the TargetProperty and Path?

The target properties are the ones PARAdoxiBLE pointed out. Since they are defined on the empire file, the path is most like ClassEmpire.

4. Am I correct in assuming that the operation called for editing the given values would be subtraction and addition respectively?

You could use subtraction (or addition of a negative number) to reduce the values by an absolute amount, or you could use division. Of note here, modifiers are processed in this order:

1. Addition and subtraction
2. Multiplication and Division
3. percentage bonuses (these are added together before being applied.)

If you are simply wanting to decrease the manpower cost, just set ManpowerCostReduction to smaller value like 0.5 or 0.2 then all the troops will have reduced manpower cost, making ground battle bigger.

There is modifier but if you just want a value modified unconditionally by a static value, just change the base value. That's all.

For the designating the path, I would recommend referring to existing mods. You can find mods (from Steam Workshop) at Steam\steamapps\workshop\content\392110 . It could be confusing for beginners to write that so having a working example would help a lot.

I appreciate the responses, will be sure to look at mods before the weekend is over.