Great tips. BUTT most times when this happens you don't have the luxury of standing in the water like in the video.
I feel you brother. Assuming you are in deep water and the canopy is laid back on the water, you are in the suck. No magic there.
If you are lucky you still have your board.. That helps a lot to provide resistance to get the kite relaunched. If you loose the board, stay deep and kick against the wind as the puffs come.
On its back like you stated, you have to get one side of the kite flying, and as you know, the only way is with the steering line. Whichever side flies first will slowly shed the water off the canopy. I work mine from straight downwind to the edge of the window seeing what sheds the water soonest. It always takes a long time in light wind, but from my experience, it always happens, so keep at it. Once you are there, it is like the magic (and obvious) Switch video. The best thing from that video was to take all the power out of this kite which will help prevent backstall. Hope that is helpful.