I raised the issue of contour lines in beta testing and their should be some pictures of the issues in that forum and no answer could be found if I recall at the time. All colours clash with other colours used in the game, browns, whites, greys, yellows, black clash mainly with roads, tracks, dirt roads, railways, blues clash with rivers, black and greens clash with forest and woods and not very visible and when they are can be mistaken for roads. Reds and yellows clash with roads in the map, Thickness did not matter. In very hilly country, all the contours and other map features formed a confusing pattern and made it difficult to identify what was what. To get what contour lines should look like on a real paper map, does not seem to work in AB very well.
Basically I do not bother with contour lines and just tweak the hill shading or go by the ISO map or the HGT option or use LOS to build up a mental picture.