More Fortuny! Yes, More!
This is an overall pattern, so matching across the hem will cause everything else to read properly. This is a horizontal line and if the pattern reads smoothly along the hem, the inevitable mismatching above, won't feel like a mistake.
I started by matching the center backs, and basting the interlinings to the two pieces.
I've used the carbon paper to transfer this point to the back.
You can see the mark pointed out by the arrow.