Thanks a lot for responding Eric. The main style they're going for is, Stylized with realism, hope you understanding what it means, kinda like Pixar animated movies
Metallic and roughness are black and white (o-1) value only like Eric said. This is why they won't accept and RGB value and only a slider in your experience.
Eric, this is version 1 of the nMaker, but I used another process (not very accurate) to generate the maps. Here are the comparative (I had forgot to do) Download nMaker1
Thanks for the feedback, Eric! I'll take a look into the post process or maybe deal with the textures directly. Didn't know that about the forum, you are correct they are PNGs. Will fix that.
And there you go, finally the water drops on the windshield. Thanks to the people who helped me make it, specially @Obscura and @Eric Chadwick . This is still under development, though.