Heads up: I merged 4.20 and everything works as far as I can see. While doing so, I noticed that there is a new decal blend mode called Ambient Occlusion. This sounds promising. But it seems that this type of decal really is for AO only, the other pins aren’t even enabled. I don’t quite see the usefulness in this, but what do I know? Anyway, maybe I can glean some insight into decal AO from this and incorporate it properly into the custom decal blend modes.