A part of the wires is attached to the upper wing prior to its installation. In the center, the aileron cables that will come into the fuselage (typical to D-V version only. But everyone here knows about this...):

Lower wings glued in place with the wires that go to the engine and already help give rigidity to the lower wings.

Fitting the upper wing:
First, the jigs, which have been drawn on the scale plan, are attached to the lower wings with rubber-band:

After small adjustments, the upper wing goes in place.

An important step: the cabanes are glued, everything is aligned:

Then I removed the left jig to fix the V-mast. As I suspected, those tiny masts may not be strong enough to keep the upper wing in place while making the "knitting" on the wires. So I started the rigging right after, so the wires help maintain both wings together. More pics when the rigging is done.