The tonal range of the source prints looks to be only about 3 stops, so consider that in the equation. That is, expect to increase negative development or print on #5 paper, otherwise your new enlarged prints will be lacking contrast.
You can get good results with a non-macro lens. Don't stop down too much. With the RZ. don't go beyond f11 as resolution will start to decrease.
Artistically I treat this like any photograph of a found object, and I like to emphasize the imperfections and tears, etc in the original, and frame it to include the whole piece of paper on which the original image resides. Rather than using the technique as a 'restoration' technique.