Is counter-battening necessary for a sloped roof?

If the lower edge of the rafters is even and exactly aligned, a simple battens 24/48mm (S10 or S13 grading class) or a substructure with drywall profiles from well-known manufacturers is sufficient, with the axis spacing also according to the manufacturer's specifications depending on the board thickness, e.g. 30cm for the 12.5mm single-person drywall board 60x260cm.

If the underside of the rafters has larger height differences, a counter-battening with adjustable screws should first be screwed on and aligned. This facilitates subsequent work if the best possible surface quality is to be achieved, which can still exist even with grazing light. The adjustable screws are not cheap but very practical to use. In my opinion and experience, drywall profile systems are more cumbersome in this regard.