Can you tell me about the group of devotees from Madras that visited Shirdi in Chapter 29?

Certainly. Chapter 29 of the Sai Satcharitra recounts the story of a group of devotees from the Madras region (now Chennai). This group, who were travelers on a pilgrimage to Kashi, had spent a year in devotional singing and decided to stop at Shirdi for Sai Baba's darshan. According to the chapter, they belonged to the Ramdasi sect and performed their devotional singing with great enthusiasm. Their experience with Baba exemplified his unpredictable nature; he gave them eight rupees and eight annas at one point, but at other times he would send them back empty-handed. This narrative from Chapter 29 illustrates that Baba's grace was not guaranteed in the way one might expect.