Test fit, prime the front inside skins and rivet the stringers to the front inside side skins.
The center console skins are not symmetrical:
After asking Sling Aircraft is was clear why; these flanges attach to the bottom skin of the parachute box which is a kind of triangle.
Since I build without the parachute option I don’t have the parachute box, so those flanges should be left unriveted.
Maybe I will add a custom bracket to make that section a bit more ridged.
I’ll wait before I decide what to do with the misaligned holes until the connecting parts are in.