After the commotion of finding those wood blocks in my rudder I could close the top rib again.
First I had another good look to check that nothing was left behind.

Next I rechecked the torque on the nuts that hold the lead counterweight block and reapplied some lacquer.

Then reclosed and rivetted the rib in with the pneumatic squeezer.

Result is very good. I did a real good job drilling the old rivets out as not a single hole got oversized.
The new rivets look as good as the old ones that came out. Another job done and off the list.

Next I'll work a bit on the epoxy fairing.