Because of the direct mounting of the window sill bracket to the window, it is irrelevant how far it extends into the insulating layer. The window sill end piece lies directly on the bracket. The window sill bracket guarantees a consistent tilt. Through the screwing or glueing of the window sill end pieces to the window sill bracket, loads from below (e.g. wind load) are also carried.
It is sufficient to set a window sill bracket at the right and the left side until a length of 1000 mm and an overhang depth of 240 mm.