I wondered the same thing when I was building my Tiger 60. I saw that the angle was very small on the gauge, but went ahead with it anyway. When it came time to join the wing halves on the jig, I had to sand quite a bit more angle into the wing halves to get a good fit. I wish I could remember what angle I ended up with to help you out. You might want to set up the jigs and figure out the correct angle ahead of time to save some sanding.