Replace material in a Mesh Particle Emitter using BP when spawned using "Spawn Emitter at Location"?

Hello all!

I have created a particle system, configured it to mesh type. I’m using a separate BP controlled by player, then using “Spawn Emitter at Location” to spawn the particle. How can I override the material in BP?

This is what I have so far, excuse the spaghettiness, I’m trying to get something to work:

In cascade, I have named slots in both the general tab and in the Required tab:

It seems to be doing something, the particle now spawns with no material whatsover:
Any idea what I’m doing wrong? Thank you!