I have Meermin shoes in both Rui and Hiro lasts, as well as Alden shoes in Barrie last.My normal size is 10D in US sizing. I would say I am more in between 10DMy experience is that Rui is wider than Hiro. Even though both my Rui (shell LWB) and Hiro (suede chukka) are of the same UK size 9. I probably could have gone down to UK 8.5 for the Rui. Nevertheless, after breaking in, the UK 9 Rui fits quite nicely.My Barrie is 9.5D and they fit nicely.YMMV.