Sorry, I meant to update that original thread with my findings but it totally slipped my mind.
The shader Ryan posted seemed to work perfectly for me. I didn’t even notice that triangulation problem that he had. I originally couldn’t figure out the final step to combine the normals on the separate UV channels, but I think i got it. I can’t guarantee that this is 100% right but it seemed to work out well.
Anyways, here are the results and the full shader graphs:
The normal map plugged into the new tangent basis function is a tiling brick texture that’s mapped to UV channel 1. UV channel 0 has the unique damage sculpt normal map.
It’s important to have Tangent Space Normal unchecked on the material attributes.
Here’s the graph for the tangent basis function using the shader that Ryan posted.