Agree that Westwood didn't develop this stroke technique.
I don't know when Foster started teaching this for whitewater, but John Berry showed me how to control his ME, a real banana canoe, with a carve balancing stroke in 1983, and I'm sure he'd been using it for decades in his open and closed canoes. He called it something like "generating a bow sidewash."
Charlie Wilson taught courses on the inside circle (carve balancing) forward stroke at flat water freestyle symposia in the 2000's. Don't know about his instructionals before that, but I'm sure he knew the stroke much earlier. It naturally comes to many paddlers who experiment with heeling and bow stroking dedicated solo canoes from a central seating position, which allows the most efficient use of on-side and off-side bow quarter strokes.
In a flat water touring canoe, you will not have the dramatic turning effects you see from the highly rockered whitewater canoes in the video, which is quite good except for the confusing (to me) terminology. In all four of my solo flat water canoes, I get a better carve by heeling to the outside of the turn, rather than the inside as with a highly rockered whitewater hull—although I can get a decent inside carve in my composite Wildfire.