Can anyone tell me how dovetails, like the type used to hold a rear sight of a handgun,are sized? By sized, I mean, is there a common size or standard size, or does each company sort of make up its own size to fit the weapons within one slide size range? I would sort of assume this since so many different types of rear sights are listed by weapon brand in the sight maker's lists. Does one brand of gun tend to have the same size/angle? There is no "usual and customary" or standard size, say, that of a 1911?