@shloho I'm guessing your father had a C-case Omega before his watchmaker sold him this Quartz watch head to replace it. On the bright side, you have a truly lovely bracelet that fits a C-case Omega.
IMHO, to bring this bracelet watch back to it's former glory, find yourself a C-case Omega watch, attach it to your bracelet, and forget about modifying the Quartz watch head. Find yourself an Omega that's period correct, in good condition, fits the bracelet, and wear it in good health.
If you haven't already, read the post Learn How To Fish. This will guide you in how to find a good watch and how to avoid the stinkers.
https://omegaforums.net/threads/learn-how-to-fish.52603/
Best of luck!
Suggestion, a watch like one of the following, which are, unfortunately, not currently for sale: