Thoughts on a definitive version, with the highest quality and dynamic range? Preferably something that is available on iTunes, Spotify, or Tidal. Also I don't know if this would help but two of my other favorite classical pieces, Adagio for Strings and Also sprach Zarathustra, my preferred versions of those are Leonard Bernstein with the LA Philharmonic, and/or LSO with Andrew Schenck, as well as LSO with Michael Tilson Thomas and/or Royal Philharmonic with Charles Mackerras, respectively. Idk, maybe that might help give you an idea on the emphasis I like, although Requiem is totally different than either of those. Basically I haven't found a version that has high quality strings, as well as choir. It's usually one or the other, so very interested in suggestions.

Also, has anyone ever tried to layer Samuel Barber's Agnus Dei on top of Adagio for Strings? I think that would sound amazing if there were two versions of nearly the exact same length so that you could just simply put them together in Audacity.