Red are the thinnest, making a tighter gap and more response
Blue are in the middle
Green are thicker, making for a wider gap and longer sleep times.
Blue and Red is what Shu Takada uses in one of his set up videos.
Greens are what are in the USA 720 editions
Reds are in the Japan 720 editions
Blues you have to buy extra
The same spacers also work in Raiders.