I built one of these a few years ago right after they first came out and at that time there was a problem with one of the cabane wires being bent wrong. It was about 1/4" too long, or too short, I can't remember. A friend was building one at the same time and his had the same problem. If used, it would have thrown the incidence of the top wing off drastically. I had to make a new one.
They've probably fixed this by now, but it might not be a bad idea to check it, just in case...