Simply, this mod works by copying the DLCs XComContent.ini and instead of using the + sign at the beginning of the line, it uses the - sign to remove the dlc items. Every single item is listed in my C:\SteamLibrary\SteamApps\workshop\content\268500\648789483\Config\XComContent.ini

I then commented out the lines that I wanted to keep in game using the ; before a line. So, if you see this:
;-BodyPartTemplateConfig=(PartType="Torso", DLCName="DLC_1", TemplateName="DLC_30_Torso_A_M", ArchetypeName="DLC_30_SldCnv_Std_GD.ARC_Torso_A_M", Gender=eGender_Male, bVeteran=false, ArmorTemplate="KevlarArmor", SetNames[0]="DLC_1_A", CharacterTemplate="Soldier")

it means I wanted to keep that particular torso in the game. If you didn't like this torso, you could remove the "comment" (indicated by the ;) and it would be removed. If there is a style that you like, say you're really into bare chested dudes, you would find that particular torso and add the ; to restore it to the game.

To create a template, like I did at the end of the ini, to allow the visual look of certain parts (like torsos, legs, etc), find the lines you want to duplicate on to other tiers, I'll use the bare chest as an example:

-BodyPartTemplateConfig=(PartType="Torso", DLCName="DLC_1", TemplateName="DLC_30_Torso_M", ArchetypeName="DLC_30_SldCnv_Std_GD.ARC_Torso_Bare_M", Gender=eGender_Male, bVeteran=false, ArmorTemplate="KevlarArmor", SetNames[0]="DLC_1_Bare", CharacterTemplate="Soldier")

This line basically says remove the "DLC_30_Torso_M" which is a KevlarArmor template from the game. We have to remove it because is was added with a + in the original dlc ini. We want to copy this line, paste it as a new line, and make a couple of edits. First is to add a + instead of a -.

+BodyPartTemplateConfig=(PartType="Torso", DLCName="DLC_1", TemplateName="DLC_30_Torso_M", ArchetypeName="DLC_30_SldCnv_Std_GD.ARC_Torso_Bare_M", Gender=eGender_Male, bVeteran=false, ArmorTemplate="KevlarArmor", SetNames[0]="DLC_1_Bare", CharacterTemplate="Soldier")

Now, we can not have two templates with the same name. So, we need to add something to the TemplateName to seperate it. I usually add an extension that tells me the next tier armor I want it to be. In this example case, we'll add _PLT_ to signify that it is going to be a plated armor template. I could have named it anything, such as _PRED_ or whatever, just so long as no other template is named the same.

+BodyPartTemplateConfig=(PartType="Torso", DLCName="DLC_1", TemplateName="DLC_30_PLT_Torso_M", ArchetypeName="DLC_30_SldCnv_Std_GD.ARC_Torso_Bare_M", Gender=eGender_Male, bVeteran=false, ArmorTemplate="KevlarArmor", SetNames[0]="DLC_1_Bare", CharacterTemplate="Soldier")

The ArchetypeName is basically what look the game is going to pull, so don't mess with it unless you want to end up invisible. The next thing we want to edit is the ArmorTemplate we want this new armor to replicate into. There are PlatedArmor and PoweredArmor and each with a Light, Medium, and Heavy. So, we'll change "KevlarArmor" to "MediumPlatedArmor"

+BodyPartTemplateConfig=(PartType="Torso", DLCName="DLC_1", TemplateName="DLC_30_PLT_Torso_M", ArchetypeName="DLC_30_SldCnv_Std_GD.ARC_Torso_Bare_M", Gender=eGender_Male, bVeteran=false, ArmorTemplate="MediumPlatedArmor", SetNames[0]="DLC_1_Bare", CharacterTemplate="Soldier")

Lastly, the new setname convention could be a cool feature, but most likely you won't want to be restricted to certain parts so I would suggest removing it. However, if you want to only have certain arms and legs options for particular torsos, creating a set would make sense.

+BodyPartTemplateConfig=(PartType="Torso", DLCName="DLC_1", TemplateName="DLC_30_PLT_Torso_M", ArchetypeName="DLC_30_SldCnv_Std_GD.ARC_Torso_Bare_M", Gender=eGender_Male, bVeteran=false, ArmorTemplate="MediumPlatedArmor", CharacterTemplate="Soldier")

And that's it, basically. You now have a bare chested option for your Predator Armor. You have to do this for each part you want to copy to other layers. I recommend sectioning them out like I have done in the ini already. You don't really need to do the arms, as they keep the same look throughout the game. Hopefully this guide isn't too confusing.

You could, if you were not subscribed to this mod, edit the original DLC ini and do something similar. Regardless of which one you edit, make a backup copy of your edits in case the original mod authors make update and you risk losing your edits.