Excellent presentation. At minute 13:35, the diagram shows the minimum drag speed and max L/D to coincide. The maximum L/D should be to the right of the point shown. Graphically it can be derived by drawing a line through the origin (0,0) and extending it to the point of tangency to the polar curve. That point will be the best L/D speed and the slope of the drawn line will be the L/D value.
I attended Mr Anderson presentation many years ago. Learned a lot and have a VCR tape of the presentation. Your link is basically the same, but a more professional production. I had intended on using it during ground school, if I ever started to teach. This link is one of the films he showed. Very enlightening.