Vintage Omega 1920-1930?

Hello,
I have had this watch in my family for years, since my grandfather who was a watchmaker died, but now we both lost our jobs due to this COVID craziness so unfortunately a time came to sell it.
I read forum guidelines but I could not find this watch in the search and in here: http://www.omegawatches.com
I managed to find following information about it:
http://www.ranfft.de/cgi-bin/bidfun...EVAjJvm2G4yk89YqEgKjaIDhqRLeZaVHYrtgHSgvljcYs
The diameter is 26mm (women?) and there is a crack in the dial.
It is clean and works fine... Actually it is very accurate.
I would greatly appreciate if you could help me to find out more about this watch, it's price and best place to sell it.
I do not need to sell it immediately but in a couple of months for sure.

I have seen a few rough ones with worn plating sell for around $200. I picked up a gold plated one (shot plating) for $100 AUD.

You are right, it is roughly between 1920-1930. The movement is a 7' million serial, the case is 8 million indicating it is on the later end of 1920.

I actually like the silver models, they look great (I'm assuming its silver, does it have a hallmark?).
I restored my gold one, I won't ever sell it, but I'd estimate $500-750 AUD for value for mine.

If you get ready to sell it, PM me on here and we can talk.