I'd certainly be interested in being challenged by an argument or two, but in no way do I have 6 hours to spend listening to the whole case.
I did skip ahead in it and listened about the canal experiment in which a boat traveled 6 miles down a straight canal and was visible from the starting location the whole way. I would say to that that the water was not "standing water" as video footage clearly shows the water flowing, and water always flows from higher ground to lower ground, and therefore, the surface of the water at the start of its origin will always be higher than the place it flows to (or it would not flow there). This could effectively mean the man conducting the experiment in the canal water was at a higher altitude than the boat was 6 miles away. In effect, the water surface may well have been more or less flat over that distance.
I'm assuming the experiment was actually conducted and expected drop in altitude was as claimed.
I think clearly, if the earth was flat, there would certainly be much more ample evidence of it which simply does not exist, such as a photo from an airline cruising at 35,000 feet on a very clear day that shows things much farther away than is possible with a round earth.
Sears Tower, Chicago, observation deck, 103d floor or something. Millions of people have looked out over Lake Michigan and noticed the curvature. No special glasses, strings, wires, cones, or education required, intuition and an artistic sense suggests it, a yardstick, bubble float and an impromptu set of sawhorses will confirm.
I appreciate the challenge to think outside the box, but this whole flat earth thing is like telling me to cease thinking.