What are the two most prominent and detailed Guru biographies suitable for Parayans mentioned in the preface, and who authored them?

The preface highlights two primary, detailed poetic biographies that are considered suitable for Parayans and Saptahs. The first, as described in Chapter 0, is the well-known 'Brihat' or 'Thorale Guru Charitra,' a sweet and graceful work written by Shri Saraswati Gangadhar about Shri Samarth Sadguru Narsimha Saraswati Maharaj. The second significant work mentioned is the 'Shri Sai Satcharita,' a more recent biography of Shri Sai Baba Maharaj. This inspirational text was authored by the late devotee Shri Govind Raghunath, also known as Annasaheb Dabholkar. The preface concludes by stating that apart from these two, no other works of such detail are found.