Thanks for listening to our issues. By 'use external materials' in unity, do you mean the legacy option? I tried that, but I couldn't get it to work either.
If I understand correctly, you will add an option to allow us to export a .obj from this software, import the model to Unity, and allow a material like this to be used with it? Then we can just assign the material to it like this.
If this can be added in the next few weeks, I don't mind waiting. We really need this program for when we start to playtest on mobile, but it would be nice to start optimizing our models sooner than later so we don't have to go back and do so many.
Thanks again for the help!