I'm trying to activate CRAY using metal that is layered under more CRAY. Is it even possible to use layered CRAY? Does the metal doing the sparking have to be on the top layer? What are the limitations of stacking CRAY? I can't seem to find much info about it online, the CRAY page seems a bit lacking in this area.
Stacked cray works just like normal cray, just be sure that adjacent metl is "visible" to it i.e. if you have a stack with metl and some other particles, metl should always be on top of that stack, so adjacent cray will be able to "see" it.