bought castings / ring mounts

[trialuser]

I have never used a bought ring setting before. I need a 3 stone setting (4 - 5.5 - 4 round 18W) and I've found something suitable from both Domino and euromounts, with a preference for the euromounts one.
It seems that I can't specify a ring size from euromounts.
Is this usual, Domino seem to have the option of stock size or specified size.
Is it expected that you resize the ring? Seems daft to have to fabricate and insert extra metal to enlarge it if you are buying a purpose made one, can they be tapped up a bit?
Presumably if you reduce the size substantially it will effect the arc of the setting adversely as well?
Does anyone know what size the euromounts castings are please.
Thanks

[josef1]

It varies but ladys size are around M usually

[Aurarius]

Is it expected that you resize the ring? Thanks
I've not used Euro or Domino for ring mounts, only Cooksons. Their wedding bands are available in a big range of specifiable sizes, but their other ring mounts are a fixed size, most of their ladies' rings being L, M or N and their men's Q. I think the reasoning is that the job of resizing is a only a few minutes' work so it's not a major inconvenience, and since the mount is sold in an unfinished state you're going to have to spend proportionately more time buffing and polishing it anyway, even if it doesn't get resized.

With a 3 stone mount you should easily get away with resizing up or down a couple of sizes as long as re-shaping of the shank is done cautiously.

[trialuser]

Thanks both.
The mounts I'm looking at are hallmarked and finished which I don't particularly want but that's how they come. I need an L 1/2 so I reckon it will tweak OK.
Anywhere else I can look for a decent range?

[Gemsetterchris]

Can you not find the "bits" from either place so you can build it yourself?
As far as I know hallmarks are an option.

[trialuser]

Yes, but Euromounts is still the one size ring shank, I suppose it would be unfinished and un hallmarked though so I'd not be paying extra for that.
It just struck me as naff that potentially you might have to either insert a bit of matching metal to enlarge the ring, or cut a wodge out, reshape, and risk distorting the head.
I think individual 'bits' is the way forward.
Thanks