: Some native paddles were made with definite "power face" sides.

This is what I was looking for; and thought it worth the risk of having a "one-sided" paddle as the result. However, even the back side proved to be useful, in fact it is better for smooth cruising, when all you need is enough power to maintain the motion.

But the paddle is only slightly assymmetric in cross-section: a euro paddler would not notice the profile, but someone who has built several greenland paddles would.

: during the forward stroke there does not appear to be fast enough lateral
: motion for the paddle to really act in a fully "wing-like"
: manner, even for modern wing paddles.

It works well as one would expect since it uses the same pressure differential that a symmetrical canted west greenland blade creates, but this is amplified by the greater distance the water must travel over the curved side relative to the flat side. Exactly as in a straight aeroplane wing in a low velocity plane.

: I suppose the fact that it creates one "right" side could also be a dissadvantage in some situations.

Both sides feel like a normal west greenland but one has more bite, the other is smoother. So there is no right or wrong side and no problems such as one gets with a spooned wing. The big bonus is the fact that one can switch between two "gears" in normal cruising.

Note. My favorite stroke is rather high angle and close to hull. So the paddle I made naturally evolved to suit this style. It's only 215 long but compensates by having short tapers and high shoulders (also for natural tilt from palms of hands).