Used a AeroConversion dimple die set (male/female and nail) to dimple the horizontal (XNS-C06-04) and vertical (XNS-C06-08) angles. Deburred and dimpled the spar tunnel holes. Needed a second pair of hands to complete the nine horizontal holes.
Tried to fit a Stanley flexible head riveter (for pulled rivets) into the spar tunnel but it would not fit. Contacted Joe and Denise Armstrong, builders of XenosB project
https://eaabuilderslog.org/?s=Parms who uploaded several additional photos to 08/16/2018 showing the XNS-C06-05 installation. Examination of the photos indicate solid rivets fastening XNS-C06 -04/-08 to the spar tunnel. Finding a second pair of hands and the right bucking bar will be challenging.