Electrical rough-in installation attic expansion sloped roof

Hello everyone,

in October, the drywall construction for the attic will be done here. We will carry out the electrical rough installation ourselves together with an electrical master. At the moment, we only have the following question.
Where should the cables from the fuse box run in the rough installation? There are different assumptions.
1. Along the raw floor (still under the screed) into every room
2. In the ceiling substructure into every room
3. Behind the knee wall into every room (however, the significantly larger amount of cable material would be a disqualifying factor here)

At the moment, we would properly prefer the route along the ceiling substructure. However, this raises the question for me how the cables actually get into the later wall. About half of the corresponding ceiling is constructed with a 35% roof slope. The attic is currently completely open and has no existing walls. Attached is the floor plan. The roof slope always begins at the inner dashed line.

The supply lines should not be longer than necessary. Presumably, 16A fuses are to be used. To comply with the prescribed disconnection times of the fuse (fire hazard), a maximum length of 18 m is a good guideline. 18m means from the fuse to the last socket for this circuit. The lengths are quickly reached there.

Ok. But that still does not answer the question. The length should be adhered to, one way or another.