Can I use Quixel's Megascans blend material with a clown map instead of vertex colors?

The Quixel blend material (“M_MS_SurfaceBlend_Material” by default from the Bridge Plugin) has a lot of really cool stuff built straight into it. I’d like to use all of it, except the vertex colors.

Looking inside, it references material functions (MF_MaterialBlend) that appear to point toward vertex colors.

In a perfect world, I’d swap out the “Vertex Color” and “Input Vertex Color (Scalar)” nodes for something that lets me use a clown mask… but I’m not smart enough to do that myself.

How do? Or is everything built specifically for vertex colors?