Is it permissible to use hydrogen peroxide to whiten some hairs on the head, and does the ruling differ based on the quantity used?

"We do not know of any evidence that prohibits a woman from dyeing some of her hair white while leaving the rest black. The default ruling in this matter is permissibility. Therefore, it is permissible for a woman to dye her hair in a way that makes some of it white and the rest black, provided that it does not cause harm or involve imitation of disbelieving women. The ruling does not change based on the quantity of the material used."