Crowd Manager – how to make ai separate/spread more?

It would be really easy to add this C++ function.

Right-Click on content browser → Choose Create new C++ File → choose blueprint-library name it and create it.
In the generated C++ header file add the following:

.h

//Includes to add
#include "DetourCrowdAIController.h" //Not sure about this one -> just in case.
#include "Navigation/CrowdFollowingComponent.h" 
//...
//Class declarations auto-generated...
//...
public:
    UFUNCTION(BlueprintCallable, Category = DetourCrowd)
    static void SetSeparationWeight(UCrowdFollowingComponent* inCrowdFolowingComponent, int32 inWeight);
//... Add anything you want
// don't forget to close the class declaration score with "};"

In .cpp file this implementation

void UYOURCLASSNAME::SetSeparationWeight(UCrowdFollowingComponent* inCrowdFolowingComponent, int32 inWeight)
{
    if(inCrowdFolowingComponent)
    {
         inCrowdFolowingComponent->SetCrowdSeparationWeight(inWeight, true);
         inCrowdFolowingComponent->SetCrowdSeparation(true, true); //Just in case it is not enabled.
    }
}

Save and Compile

Now you will have this Function available in your Blueprints.