In this Tutorial i will explain how you can increase the Default Inventory Size.
1. Without PlayerTemplate:
Add the Interface SP8_BPI_IncreaseMaxInventorySize to your Player BP.
2. Without PlayerTemplate:
Open the Interface Function SP8_IncreaseMaxInventorySize.
With PlayerTemplate:
Overwrite the SP8_Overwrite_IncreaseMaxInventorySize Function inside your Player BP.
In this Function you can put your logic and return the Integer on how much bigger you want the Inventory Size to be.
Of course you can put negative Numbers as well.

Since v0.2: The PlayerTemplate will get the Stat Value of the Gameplay Tag StatType_MaxInventorySize and will add this Stat as adding Size.
You can set the Gameplay Tag inside the ClassDefaults, if you use the PlayerTemplate.
Of course, if you overwrite the Function, it won’t get the Stat Value anymore!