Original N frame adj rear sights are tough to find but K frame pre-wars are out there. They are the same sight but the tang is shorter.

If the revolver has had the tang slot milled out larger anyway, an available K adj sight could me fitted with a new entire tang portion to make up for not only the Nframe length which it would need, but any over size width from the post war sight mod.

It'll make the addition of the front sight blade somewhat smaller (not as tall) too. With the post war adj sight on it, the front sight blade is going to be quite high. Part of that overly tall 'look' is a the absence of a bbl rib of course.
Just another suggestion.
Ain't projects fun..!