You got the idea about DL. I know the GC course mentions only 5 books and this is what I recommend for one sitting for direct learning. However I have applied it to more books than just 5. I chose 12 books on the topic that interested me and had 2 complementary books that I just shuffled into the sessions. Then I did 3 DL sessions. The results are rather pleasing and still developing it seems.
I most certainly wouldn't limit the DL experience to only the suggested minimum books I find more seems to be better. where I had used only 3 or for books on the subject I wanted to master it has been a lot less noticable whether I have been successful or not.
Alex