Can you provide the specific details of Sai Baba's unusual sleeping plank as described in Chapter 10?

Certainly. Chapter 10 gives a very precise description of Sai Baba's sleeping apparatus. It was a wooden plank measuring four cubits in length but only one span (approximately 9 inches) in width. This remarkably narrow plank was not on the floor but was hung from the rafters of the mosque, suspended at both ends by old rags, functioning like a swing. The chapter adds that while Baba would lie or sit on this plank, lamps would be kept burning at His head and feet. A key detail emphasized is the mysterious nature of its use, as no one ever witnessed when He climbed up to or descended from this precarious sleeping place.