Guided studies

I know the lesson guides are being prepared, and I'm not trying to pressure. (I promise I'm being patient, in spite of all my questions.)

However, what are your thoughts on purchasing the study guides for the books mentioned in the program outlines? This would be to get started while waiting for the full lesson guides. For example (as I'm looking specifically at year 3), the Children's History of the World or the one about birds.

Would this just be a waste as I'd be doubling up, or a smart move because the lesson guides won't be available in the next six months? (I know the curriculum writer is doing a ton of great work right now. I so appreciate it all.)