While one is seated, should the worshiper raise his hands after the the first Tashahhud, or wait until he stands up to raise them?

It is authentically reported in the Prophetic Sunnah that the Prophet, peace and blessings be upon him, would raise his hands when he stood up from the two units (rak'ahs). This is what Ibn Umar, may Allah be pleased with both of them, used to do, and it was narrated by Al-Bukhari. It was also narrated by Abu Humayd Al-Sa'idi, may Allah be pleased with him, in his description of the Prophet's prayer, peace and blessings be upon him. Imam An-Nawawi stated that this is the correct view, and it was held by Ibn Al-Mundhir, Abu Ali At-Tabari, Al-Bayhaqi, and others. It is also the madhhab (school of thought) of Al-Bukhari and other Muhaddithun (hadith scholars). Shaykh Al-Islam Ibn Taymiyyah mentioned that raising the hands is a Sunnah when the worshipper stands up from the first Tashahhud, and this is a narration from Imam Ahmad. Shaykh Ibn Uthaymeen mentioned that raising the hands occurs after the worshipper has fully stood upright. The Permanent Committee for Scholarly Research and Ifta stated that raising the hands occurs when standing up from the first Tashahhud, along with the Takbir, after beginning the transition from sitting to standing.