Ahh particles and VR, they do not like each other. Some particle effects look very fake in VR.
Edit:
Thinking a bit more about all this. Easiest way to make it is to C++ into mordor.
Yes i know you may not know C++ and it may be scary.
But follow tutorial about how to setup visual studio.
Then look how to make simple blueprint node (this is very easy).
And finally hardest part is writting those loops that generate shapes.
But because it is C++ you probably can find code examples that do just what you need.
At that point it is matter of translating that code into unreal C++ code.
C++ is probably easier because blueprints can get messy for such code.