Finally circling back to this. I can say that it works as expected. Removing the BNC is the most cumbersome part, but not terrible. You will need a soldering iron that can reach at least 430 C / 800 F.
The pics were too heavy for email so I updated the whole procedure in the Wiki
Serial output works as expected.
I haven't tested mechanical stability, but the gluing looks sturdy and should last a while.
* I have 4 or 4 Addaloggers with broken sd card slots (either the spring is broken or the full part came out). Has anybody tried to fix those? I have been buying new ones since it's a 20 dollar board, but I was wondering if somebody ventured into removing the SD reader and soldering a replacement