I'm calling upon those who may really know this topic. I've been looking online to see if there's a NEW critical edition to the Mahler 10th Adagio. There doesn't appear to be one. There lots of sources for - and references to - Universal's publication of the 1964 critical edition put together by Erwin Ratz. But I know that Frans Bouwman and others have worked on making numerous corrections. To my ears, it sounds like the Barshai completion incorporates numerous small corrections in the Adagio. Does anybody know if that is, indeed, the case?
I believe that Bouwman had made his corrections available online at one point, but I might just be imagining that.
I listened again to the Barshai version with Vladimir Ashkaenazy conducting (Exton, I think). The first movement is the best I've ever heard it, but I think Barshai makes a mess of the remaining four movements. His orchestration is overly busy and 'fussy' sounding, without addressing what the big-picture issues within the last four movements. Just one person's opinion.