Hello there.
While I cannot provide any Omega related expertise, what I can say is that you need to be a little more specific if you want information from those who have it and are willing to share.
What is your budget? What diameter would satisfy you? Keep in mind some of these watches are very small, sizes ranging from 33-35-37mm. These come from a period when men's watches were not as big as today, but I'm sure you know that, therefore the bigger sizes are rarer.
As with any watch related hunt, there are two constants: time and money.
There are a lot of brands that produced this style of watch, ranging from the affordable generic brand(Hoga, Jovial) to the higher end of the spectrum(UG, Omega). It all depends on your budget. Also, these are
very, very often redialed. You need a lot of research before getting into such waters.
Also, make sure you have a watchmaker who is willing to service one of these. Service costs will be higher than your average vintage watch.
Search function yielded these and they're a very good start:
https://omegaforums.net/threads/jumbo-moonphase-2486-2.84629/
https://omegaforums.net/threads/considering-a-moonphase-your-favorites.106528/page-3
Good luck in your hunt!
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