I think cutting the tip's just makes for better roll rate on this plane because the WS is too long for 3D. I bet it would fly pretty good 3D if you took the few inch's out of the center of the wing's core and left the tip's. I have the PA Electric Shock and it 3D's bad ass with the tip's, it has a pretty short over all WS though.

Don't get me wrong I would never recomend cutting the root out instead of the tip's I was just saying seems like the WS is just to long. I wonder if that guy ever solved his wing rock prob?