Hello Jim,
You bring up something that I don't believe has been covered in a single book: a comparison of say, RAF vs. Luftwaffe training and results. This along with the changing war situation as time passed. Here's an example of what I mean:
https://www.rafmuseum.org.uk/researc...-training.aspx
Also, since the RAF had a number of foreign, non-Commonwealth volunteers with varying levels of experience, I wonder how they were trained or not.