Two Beat Kick Resources
Long Distance Open Water Swimmers:
This is Shelley Taylor Smith but great visual that you can get a lot from. She is much shorter than you so her cadence isa lot faster, and the kick to me appears pretty big & wide…but all the timing elements are there.
Here is a video of me, who you have seem swim before, but you can study this if you like…no underwater though
Here is another with my friend Mandy narrated by her dad Stuart, both froends of mine and both swam the english channel with this stroke. This video has a bit of slowed exaggeration but it’s narrated and annotated.
Here is a dryland video by Celeste whose picture in the book you liked so much