Frustrating rigging mysteries. The lower starboard wing is leveled at 0 degrees at the root (incidence fixed by the winglets) and is 0 degrees at the struts (incidence set with a wire). Good so far. The upper starboard wing is also 0 degrees at the root (fixed by the center section) but comes in at -1 at the struts...so with 1 degree of washout. I'd really rather eliminate this but can't quite figure out how. It looks like lengthening the rear strut about 3-4mm might do it. But I could live with the -1 (on the meter) of washout, i.e. TE is +1 relative to the LE. Relative to the engine thrust line/aircraft center line this is +5 at the root and +4 at the struts.

OK. Now what about the port wing? The lower port wing root is also at 0 degrees and 0 degrees at the struts (with the incidence wire in place). But now what about the upper wing? It's 0 degrees at the root...but -2 at the struts. Where's that extra degree coming from? I measured the length of the struts+brackets (i.e. top of lower wing to bottom of upper wing) both front and back and the lengths are the same. So where's that extra degree coming from and how can I get rid of it?

From our discussions so far, it seems like that extra degree on the left side (essentially working like left aileron) might cause just the sort of left-pull it's experiencing.