Continued with the leading edge skin which was more work than expected due to the tight fit.
The tie down bracket has not sufficient clearance:
I removed the skin and enlarged the cutout with a 4 mm file:
With help of an aluminium angle profile and a strap I got the skin in position:
First insert the clecos in the main spar, thereafter squeeze the ribs in position!
Inside view with the stringer:
The standard 4 mm rivets are 10 mm long, just a bit too short where the splice plate is located that connects the inside and outside piece of the main spar; I used 13 mm rivets:
I had a few light corrosion areas on the outside of the skins, I removed all plastic and scuffed the skins with Skotch Brite and de-greased them.
Next I lowered the tables and rotated the wing into position for attaching the fuel tank: