According to which madhhab or Sharia is the mahr set at 19 mithqals of gold upfront and the same amount deferred, in order to avoid zakat?

There is no mention in the schools of Islamic jurisprudence or the sayings of scholars that the maximum dowry is nineteen mithqals. The maximum dowry has no legal limit, as evidenced by Allah Almighty's saying: (And if you wish to replace a wife with another and you have given one of them a qintar [a great amount of wealth], do not take anything back from it. Would you take it in injustice and clear sin?) It has been reported from the Companions that they married with large dowries, such as Umar ibn al-Khattab, who married Umm Kulthum bint Ali for forty thousand dirhams, and Ibn Umar, who paid ten thousand dirhams as dowry for Safiyyah. Scholars have agreed that there is no maximum limit for the dowry; their disagreement lies only in its minimum amount.