Is it permissible to invoke blessings upon the Prophet (peace be upon him) during prostration in prescribed prayers, and does dedicating Friday for that purpose constitute an innovation?

"Praying upon the Prophet, peace and blessings be upon him, is a remembrance of great reward. Allah has commanded it, and He and His angels pray upon him. The Prophet, peace and blessings be upon him, promised that whoever prays upon him once, Allah will pray upon him ten times in return. It is recommended to increase prayers upon him. Whoever dedicates all his prayers to him will have his worries taken care of and his sins forgiven. It is especially recommended to increase it on Fridays, because the prayers of the Ummah are presented to him on that day. It is permissible to pray upon him during prostration, as it is one of the positions where supplications are answered, provided one begins with praising Allah and concludes with it. However, dedicating Friday specifically to praying upon him in every prostration of the obligatory prayers has no basis, and the fundamental principle in worship is to adhere to what has been ورد in Islamic law."