the "obviousness" of the connections is tricky. The blending is in the linear RGB space. I initially tried sRGB but it was terrible. I'm not sure how to improve it. At the moment the interpolation is done through the varyings between the vertex and fragment shader. This is quite limiting.
About the lack of deliberate choice, in theory you can reach any rgb color. In practice this is limited by the initial colors I chose (they are smoother than pure RGB-CMY). I'm not sure how much of the RGB space I'm missing.
For the antialiasing issue I'll look into it. I'm not sure I correctly set the AA in webgl. Could also be due to some issue with the size of the canvas
Thank you again!