> The fact that full aerobatic and military jets do, is because they usually don't have that curved 'fish' shape cross section, but are usually symmetrically shaped on the top and bottom of the wing.

Fair enough, it is symmetrical, but still has a lot of shape to it - only time I've been inverted was in a grob 103, and was a passenger for that part of the flight, here's the cross section of it's little sister which is also fully aerobatic:

https://en.wikipedia.org/wiki/File:Grob_G_102_Standard_Astir...

My point in the gp post was that since one can fly inverted, the shape of the wing is not the only fact. I think you and I are saying the same thing.