I got an Eterna WWW dirty dozen watch, it actually started my watchmaker carrier (if we can call it like that as it is just a hobby), i found it in the dirt as a metal detectorist and a watchmaker, John Senior restored it for me. You can read the story on mwrforum, unfortunately the links to the mwrforum do not work without registration any longer so cant link it here. We also had an issue with the dial, but a different sort, as the watch was in the soil for probably decades we had crystals grown on the dial (a little water and probably chemicals got inside) but fortunately it was saved.
Unfortunately i do not hold the knowledge what would help you here. I am very interested as what sort of paint is used for dials and hands.
Just in case you decide to register or if u registered already:
https://www.mwrforum.net/forums/showthread.php?84492-Freshly-dug-part-deux-Eterna-WWW-found-by-metal-detectorist