Are there specific, detailed biographies of Sai Baba that are recommended for devotional reading to deepen one's connection?

Yes, Chapter 0 specifically highlights a key text for this purpose. The sweet, inspirational, and grace-filled biography written by the late devotee Shri Govind Raghunath, also known as Annasaheb Dabholkar, is highly recommended. This work, titled Shri Sai Satcharita, is described as the biography of the 'modern crown jewel of saints.' Along with the Guru Charitra, it is noted as one of the only comprehensive and detailed poetic works of its kind, making it particularly suitable for Parayans and Saptahs to deepen one's spiritual connection.