I found it interesting that the lead car would get some drag reduction out of drafting. Also look at how the following cars can be so far back and still see improvements. Note how the template seems to have little to no effect on drafting numbers. I'm guessing they have more to do with effects in the broader air stream. We have seen this in the CAD studies members have shared here- air velocity behind the car is much lower than the surrounding stream. I'm not sure how that all comes together in the end but it's something to think about.
Also strange how the trailer he draws does not fit the template. Perhaps there is implied plan taper and edge radii?
I have to admit I don't have the book (imagine asking your dad for money to buy an aerodynamics textbook) but will get one as soon as I have any significant income!
