in the last couple of days I've spun Delay 1968 (didn't like), and Soon Over Babaluma (which I liked a lot, pretty much as good as the Damo albums, at least on my first impression).
Going by your rankings I've already heard all the best ones. But I'll be running though their whole discog as I read the book, so maybe some of those later albums will take me by surprise. I'll definitely want to look into those bootlegs. I love a good lengthy jam (been getting into The Dead a lot recently too) and I know Can have plenty where that came from.
The book is really long btw (nearly 600 pages). So if you're hoping that the book crams in as much info as possible I think you'll be pretty happy with it. I don't know too much about Can's history beyond the basic stuff, so most of their story should be new to me, which is exciting.