That's a beautiful node setting. I will try to explain some problem first:
You shouldn't use emission shader for your output, if the output is Color and you want that color directly show on your screen, please directly connect the Color socket to Output Surface socket. This post elaborated more detail of color output setting
What you mean too fast? Human ...
You mix nodes with Mix SHADERS use "fac" to blend between both influences. And then connect that last node to the Material output.
Here´s a 4 minute vid on how to make rust: https://youtu.be/hccqcCIGGUw
When you're done, connect it to the second plug on your mix node (the first one is your glass shader).
Assuming that you don't want to apply the shader to the actual face of the texture, all you need to do is plug the alpha of the image texture into the mix shader socket. This should make the faintly discoloured box disappear, as it will only apply the ColorRamp to anything that isn't the face.
If this doesn't work, then check: