Good questions.
1. Watching the video again, I think John actually is cutting with the long edge through most of the demo despite that comment, but the cut can easily be done with either edge on either side, and we use both all the time. When you cut with the false edge, what starts out as the false edge becomes the true edge at the end of the cut as the grip slides in your hand so that your knuckles face the opposite edge from where they started. I'm not quite sure how you're ending up with palm on top and thumb underneath (the thumb should always end up on the side facing you), but it sounds like you may just be gripping it a little too tightly and not letting the sword rotate in your hand. A supple grip is important and makes a lot of transitions easier and less awkward, but it's a difficult thing to describe in words.
2. The video is not a direct interpretation of a single source, but a general interpretation based on multiple sources that can be adjusted to the source at hand. For instance, John is cutting with hand-foot agreement (left hand forward : left foot forward and vice versa), but several of the sources say to step right and cut on your left. The same cut shown works whether you are stepping right or left, though mechanics may vary slightly and you may need an extra step with the left foot to finish the cut depending on where you end up. The sources I've looked at generally don't specify (or prohibit) any footwork beyond the first step, so we presume it to be situational as needed. There are some passages where I can admit it's a little hard to see how our version of the cut fits the text at first, but in this one from Ringeck I think it is particularly clear:
This is how you can Absetzen ("set aside") the cuts from above with the Krumphau: If he attacks you from his right side with an Oberhau, step towards his left side with your right foot and put your point in the Schrankhut. Practice this from both sides.
Schrankhut is basically a more vertical hanging guard with the hilt clearly up and the point down, and is an excellent protection against an oberhau. In this case, you're setting up a bind underneath the sword rather than over it as in some other applications of the technique like John was showing. Cutting over the top in a windshield wiper motion to get underneath a descending cut is inefficient at best, dangerous at worst; cutting down from behind is a much quicker way to get there, and it directly attacks the person, not just the sword. The instruction to practice it on both sides is important because you can't actually cross your hands when cutting on the right side no matter whose version of the krump you use. I suspect it is named "crooked" mainly because you will use the crossed hands version more often since most people attack you from their right more than their left. Again, this is the most clear example I can think of at the moment, not the only one.
As for the list of images it matches, I don't have it handy or time to find them all myself, but I know just the person to ask, so I'll see if I can get that for you.
