Go to the BP_MasterInventory and go to the Find Empty Slots function, then add a new input called WeightCheck and set its type to Boolean. Then add another input called WeightCheckAmount and set its type to Integer.

Add the highlighted nodes shown in the image below, location at the top of the image.

Next go to the Search Equipment for Empty Slots function in the BP_EquipmentInventory and add a new input called WeightCheck and set its type to Boolean. Then add another input called WeightCheckAmount and set its type to Integer.

Add the highlighted nodes shown in the image below, location at the top of the image.

Add the highlighted nodes shown in the image below, location at the top of the image.

Now play in editor to compile the blueprints, this might take a while to load.