How to use finalToon for two different colours of lines.

answer: first, don't apply two different finalToon effects, but apply two different finalToon materials to an object; assign two different material IDs to the parts of the object which should get different line styles. Next, apply a multi/sub material and put two finalToon materials into it. In each finalToon material, enable the local line styles and adjust one color 'a' and the other color 'b'.