Maya Toon Shader Experiments

To effectively achieve the Saul Bass art direction for my animation I need to somehow get the same 2D graphic design effect that my concept art achieved. I was told that the way forward with this was with Maya's toon shaders.

Below are some of my experiments so far in trying to create that 2D stylisation that I want to bring forward. They are pretty cool but I'm not too keen on the harshness of the different colour tones and I need to somehow get a nucleus into the image as well so that will be my next experiment.