Installed the angles and spar doublers to rear spar. Spent some extra time reaming out the 9 bottom spar holes so that the M4 bolts align well with the M4 rivnuts. When the structure is put together there is some slight alignment variation that makes some of the M4 bolts not align well through the angle (part 9), spar doubler (part 14) and rear spar (part 7).
Also there was some question about if the bottom two rear spar holes on both sides should be upsized to M4 or upsized to allow the bottom two rivnuts install on angle (part 9) to be flush in hole on rear spar. After consulting factory tech support on 10/08/20 their response was "You do not need to enlarge the holes. The flanges have been designed to leave a gap for the rivnut flanges." I followed their advice and only upsized the bottom two holes to M4 size on rear spar for the bolts to pass through to the angle rivnuts.
Riveted the internal structure of the VS together except the top rib where will be installing the VOR antenna puck next.