Re: coupling, tucking to gear or pulling to canopy, can often be traced to CG placement? When the plane rolls 90 degrees the elevator effectively becomes the rudder? This is why some will trim their plane for neutral elevator (so the elevator is not trying to turn the plane when in KE).

That said, some planes are notorious for coupling on KE. The one that really sticks out in my mind is a Citabria.

That's my experience on the topic anyway. -Al