Which CC Watershed one? There are a few scans there.

This has the NOH version, https://www.ccwatershed.org/nova/ Vol. 8
then this
https://www.ccwatershed.org/2013/03/19/1927-bas-vesperae-et-completorium/
or
https://www.ccwatershed.org/2013/03/19/1890-organum-comitans-ad-vesperale-1-2/
or
https://www.ccwatershed.org/2013/03/19/organum-comitans-ad-vesperale/
you may find other things here,
https://www.ccwatershed.org/library/

Do a ctrl + F search for Potiron. His complete Vesperale for Sundays and feasts (so, pretty much all that you need for 1962 Vespers and indeed pre-1962 Vespers, since most people would not need accompaniment on ferial days or minor feasts which use the weekday psalms). I happen to like those; although they are somewhat less modal and require a little bit more of the melody, they're in the Solesmes style enough that they're not overwhelming if you come to Vespers thinking of Fontgombault or the ICRSP as a good model. Aside from some of the Magnificat antiphons (which I transcribe and transpose on the computer) the dominant of the antiphons and psalms is always A. I find that helpful!

(That said, it isn't for everyone, but if you want the Solesmes rhythm, that's the best bet; otherwise, the NOH is what people recommend.)