Roof pitch & knee wall height, recommendation?

One should also keep in mind that roof windows go very far up with a knee wall height of 1.5m, and cleaning, opening, and looking outside do not become easier as a result. There are additional windows for the area below the knee wall, but that makes it more expensive.

that is correct and important. but it only becomes interesting for large houses, when a third room is added in the middle between the two straight walls (or if you want 2 windows in one room). possibly it still has to be considered for a window at the staircase in the middle.