Quick update. I have been going back and forth with Caleb at ZAC and he thinks there either was some minor alignment problem with the rear upper skin, or there was a manufacturing error. He assured me that the wing is safe and that there should be no issue. I will have to live with the rivet lines not lining up (which is killing me) but at least it is consistent over the whole wing.
While waiting, I decided to pull the left wing off the bench and start working on the right wing. It is now leveled and ready for the application of the upper rear skin, which will be interesting to see if I have the same problem as the left wing.
I have committed to a space over at Kitplane Builders (www.kitplanebuilders.com) which is owned by the same people who run Aircraft Spruce in Canada. I will be moving the project there in the next month or so when someone finished their plane. There is a quick build 601xl in progress so it will be good to use as a reference. I will finish the wings in my garage, but the fuselage needs to be built elsewhere due to height issues.
