I saw the thread last night and did not watch the video until now. That is a nice idea.
I was thinking you could do something similar but only use a small hole in the side wall (like extra return), basically like in-ground is done. And connecting an external bucket to the pool through a hose/pipe to the small hole. Could use an in-ground autofill bucket and valve, just have to figure out how to mount it externally to the pool.