Another suggestion: Line up the scarf or butt joints and wire these in palce first, since they should mark a consistent position around the hull. This is how Pygmy Boats suggests stitching the hull together. Slight variations in how the ends meet can be patched up with epoxy later.

Although I haven't built your boat, I'd suggest putting a few stitches in
> each end and getting them snug before doing the rest of the hull. This
> will ensure that your ends match up. If you started from one end you might
> find a slight mis-match once you got to the other end. It can be fixed, of
> course, by loosening a few wires and pushing/pulling the panels a bit, but
> you might as well try to avoid this extra work.

> Dean