Você não pode controlar o balão de notificação. Esse foi um dos objetivos do sistema de balão de notificação. Se você quiser mover o balão ou alterar o tamanho, não use um balão.
Ideally, users immersed in their work won't see your notifications at all. Rather, they'll see your notifications only when their flow is already broken.
Notifications must be ignorable
Notifications don't require immediate user action and users can freely ignore them.
Developers and designers often want to present their notifications in a way that users can't ignore. This goal completely undermines the primary benefit of notifications because it would break users' flow. If users are distracted by your notifications or feel obligated to read them, your notification design has failed.