After the primer cured I continued with the forward floor assembly.
Sling came back to me regarding the part numbers of the outside stringers, they are the correct ones.
They also replied that the extra holes in the skin (green markings) and the strange holes that are on the edge of the stringers (red markings) are okay and could be reinforced by making doublers:
Sling 2 builder Alois informed that some holes should not be riveted at this time, this is not in the manual, thanks Alois!
So I cleco’d the other parts to the structure to get a better understanding: