In learning about typefaces, I have always been taught that small capitals are not merely scaled-down versions of caps, but are their own entity, so that the stroke weight is proper. (Sad to say too many fonts don't contain proper small caps.)
But anyway, is the same theory true for superscript and subscript figures? What I mean is, should there properly be separate figures created for superscripts and subscripts whose stroke weight matches the characters around them, instead of just using miniatureized regular figures? I've never seen a font that had these.
I'm just wondering what is in theory the most correct way, and in practice how it is done.