Tri-Planar POM Materials

Hi, I am trying to to make a set of modular walls and floors that I can drop a 2 layer pom material on using tri-planar mapping so I can easily vertex paint different materials over a building.

However, I can’t find a tutorial that covers world aligned/tri-planar in anything but the simplest of cases. If anyone can point me to a tri-planar pom tutorial or example somewhere that would be ace. I am getting very weird results which I think are to do with camera vectors or normal tangents and all that.

This is my current tri-planar mapping

And the normals bit, going into a customized UV channel, nothing going into POM UVs input.

Trying to achieve something like this but with tri-planar

Getting this:

Any help would be appreciated!