I use Dash along with brushify.io tools for landscape. Brushify supports RVT with it's landscape material, and to be able to use the same RVT I had to edit the Dash_RVT_Prop material function to change the RVT. Exposing them as parameters that you could change in the material instance (or even better in the Dash ui) would be handy. I'd like to avoid changing Dash material code as much as possible to be able to update Dash's version when a new one comes out.