The second problem I ran into with the Quickbuild doing some parts but not others (for example, riveting things together but not putting in the rivnuts) is on the cover that goes over the parachute rocket. The Sling factory made beautiful holes for the rivnuts so I didn't need to drill them out, but there is no room to get any kind of rivnut puller in there. After talking with the Sling factory, I ended up with the choice of de-riveting everything and putting in the rivnuts, or just putting new holes in for the rivnuts a little lower. I opted to drill more holes. It is just a cover, after all.
The lower 8 rivnuts were easy, the top 2 were a little harder (even with the lower holes), but they all got in. It is hard to see where the screws are vs. where they should be, so I've included pictures and a marked up drawing.
Time to move on to next steps of this build!