Hi all.
I took a punt on a poorly advertised vintage Omega the other day and it paid off nicely. I suspected that the case was solid gold rather than plated, and that turned out to be the case.
Here it is as advertised:

It arrived yesterday and I gave the crystal a good polish and the case a light polish to remove some tarnishing.
The 351 bumper is running well and the diameter is a pleasantly surprising 34.5mm.
There are a couple of issues to address:
There's a missing index at 12 and a missing barrel bridge screw. Fortunately I've found both at the same seller and they're on their way.
The second issue is the crown.
I believe it should be a hermetic crown. Cousins has Omega hermetic crowns in a variety of sizes. Stem is 0.9mm, pendant tube is 2.1mm. Best guess at a reasonable size is 4mm and 2.0mm thick.
Cousins has a couple of GP crowns in this sort of size (pendant tube 2.0mm).
Unfortunately Cousins doesn't have a good photo for the crown they're selling, so it'll be a punt that the style will look correct (domed?).
Does anyone with something similar have any crown suggestions - either a source or sizing?