What is your final purpose? ask open questions about the content of the book? or something else?
I fine tuned davinci with a 70K words book. I split the book in sentences for a total of around 3000 sentences. When tested against arbitrary questions, but all in the context of the book, I didn’t get the expected results as it would diverge to content outside the book.
Then I went the ‘embeddings’ route with the same book. This time I got exactly what I wanted. I could ask the model any question about the book and it would answer perfectly most of the times (95%+ if to put a number).