As requested by the client I tried to maximize the available space including the staircase, master bedroom, the bathroom, the laundry and children's room.
I inserted also four dormers and two skylights.
The bathroom is roughly above the main bathroom downstairs because I think it's the best position in terms of subdivision of spaces.
I think instead that the best position for the staircase is the central one in order to divide well the service spaces (bathroom and laundry) from the rooms.