The tutorial by epic games is great as is the other. The used ‘Actor Component Interface’ type for the user variable which can be found in ‘NiagaraDataInterfaceActorComponent.h’ is not meant to be set at runtime. Since it is a UObject you can not instantiate it from blueprint and it has set the ‘EditInlineNew’ attribute which means that its values can only be set during runtime.
I was curious if there is a way around updating the beam end on tick with this type of variable, since it does basically the same. Just encapsulated within the niagara effect.
So updating a vector parameter on tick it is 
Thanks for your help and your quick response.