if you accept the argument that a GP has something in common with a winged paddle then it is probably still generating mostof the propulsion in exactly the same way as a euro paddle.

if you use a winged paddle without modifying your technique, you get no benefit. if you modify your technique, I have read that you get about a 2% or 3% benefit. people who claim 10% either had an inefficient euro stroke or else they are dreaming.

That suggests that 90 something % of the propulsion with a winged paddle comes in the same way that you get it with a euro paddle. I suspect that the same applies to a GP. Most of its propulsion happens for the same reason it happens with a euro paddle. Used inefficiently, a GP paddle still does a good job of moving a kayak along. Not all of the benefit of canting it correctly comes from the "lift" effect. Some of it comes from reduced caviation.

The similarities between the different paddles is greater than the differences.