Thank you for this video, it's really nice to hear the components be applied to a few tunes.
This is something I'm very interested in getting better at (as well as experimenting in playing both main and counter melody at once for a piece), and has reminded me of something I've not been quite sure how works before is a short throwaway part of a Tim Edey video here;
https://youtu.be/WG48kOcyt_Q?t=229 - I haven't been able to work out exactly what it is he's doing or if he's making use of his C# row. When these harmonies are involved, often it's very hard to see which fingers are active, and I find it hard to distinguish which notes are being used.
Either way there are some nice exercises here that it turns out I'm already sort of working on, but I think I shall try and pick up the tunes you demonstrated to just try and get a better working understanding of how to integrate it into tunes I already play. My goal previously was Donkey Riding, which I think it still kinda is: my plan's to see if I can manage to play it in 3 octaves at once (because you can play it on the bass, too); maybe 4 octaves if I ever get a low G scale layout.