I’m glad it’s working out. My only point about the rivets was that a good hardware store may have suitable ones.
Most shops wouldn’t attempt a repair that involved replacing a rivet, and for that matter they would probably steer clear of reusing a rim that had a pulled rivet. As long as the rim is not modified the manufacturer takes the lions share of responsibility for the part. In this case any further damage due to unknown cracks wouldn’t be catastrophic and would most likely happen due to a significant trauma. So, i would feel safe using a washer.
Honestly, i think washers do a better job than eyelets, but it adds more time to building, and machines can’t build with washers. I would bet that’s the real reason eyelets became standard as rims got lighter.