853 stays aren't available as far as I'm aware...
I am sure that Curtis offer a full 853 framed bike - stays and all
I meant 753 above ^^^ or did I mean 853
Seems they do, I must be out of date (again!)
However I just nicked this that seems to challenge the logic of using them
Cotic say this:
"Reynolds are only offering their 853 stays in the same profiles and wall thickness as our cromoly stays so they wouldn't any lighter, just an awful lot stronger (when our cromoly rear end is perfectly strong enough) and an awful lot more expensive. For the moment, we'll stick with what we've got."
Also I don't think you can cold set 853, so the frame builder needs to get Reynolds to provide them in the correct shape already and can't align the rear triangle in house. This might be a total irrelevance, but it seems like a bad thing...
Don't actually know what the stays are on my 853 Sanderson Life, would quite like to find out!
Website just states 'heat treated'.