I did find that PDF. All it tells me is that multigrade filters are available from 00-5 in 1/2 steps, and that the lowest number is the softest contrast.
Reading back through the bit about the light sensitivity of the emulsion make a good bit more sense now. I think what was confusing me is that it spends more time talking about magenta, yellow and other color filters. When I went to my enlarger, the dial adjusts from green to blue. Reading more carefully, it seems to be talking about using colored filters to filter white light coming from an enlarger with no variable contrast head.
I just thought they would spend more time talking about filter colors and giving examples of filters seemingly designed specifically for their MG paper...