Riveting of the right side rail was similar as on the left side although the fit was not as nice.
With all holes, where the pieces mate in the center, perfectly aligned the shape of the side rail was a bit bending inwards. This was not the case on the left side:
Since this seems to be critical joint I didn’t want to match-drill or up-size these holes and with some minor force I was able to get a cleco or rivet in every hole. After some measurements it was clear that the right and left parts are not identical. My fuselage kit is from 2020 and some parts even older, I hope the accuracy of parts is improved now. All these alignment issues are so time consuming…
Anyhow, right side rail is in place now as well:
Detail photo of the joint section, the side rail is still a bit bending inward but when the gussets are in place it should be fine: