Well, it is not all too complicated. ALL commercially available recordings of the "original version" are just the well known final version with Blumine added.
Then there are a few recordings of the "Hamburg version", which is tedious, as there are at least 3 Hamburg versions: the one Mahler brought to Hamburg (a heavily corrected "Budapest version"), the one which was actually played in Hamburg, and one with further corrections after the Hamburg concert - which seems to be close or even identical to the so called "Weimar version"; the last one has been recently published by the Mahler society and therefore has been recently played there and then (e.g. Hengelbrock recording); it is thus the last version before the structural change of the symphony from 5 to 4 movements. Denham does not make this clear in his survey and seems not to really know what he is talking about (e.g. dismissing the Hemus recording as bad and ignoring the fact that of the 3 "Hamburg" versions this uses probably the earliest one).
Of the Budapest version, only movements 1, 3, 5 exist. The two youtube performances (Wulff and Werner) use these movements and try to reconstruct mvmts 2 & 4 from the earliest Hamburg version (which is not easy, as things were mostly written on top of each other) - you may decide how successful. Anyway, the last version of Mahler 1 is so much better than the earlier ones...
Then there are a few recordings of the "Hamburg version", which is tedious, as there are at least 3 Hamburg versions: the one Mahler brought to Hamburg (a heavily corrected "Budapest version"), the one which was actually played in Hamburg, and one with further corrections after the Hamburg concert - which seems to be close or even identical to the so called "Weimar version"; the last one has been recently published by the Mahler society and therefore has been recently played there and then (e.g. Hengelbrock recording); it is thus the last version before the structural change of the symphony from 5 to 4 movements. Denham does not make this clear in his survey and seems not to really know what he is talking about (e.g. dismissing the Hemus recording as bad and ignoring the fact that of the 3 "Hamburg" versions this uses probably the earliest one).
Of the Budapest version, only movements 1, 3, 5 exist. The two youtube performances (Wulff and Werner) use these movements and try to reconstruct mvmts 2 & 4 from the earliest Hamburg version (which is not easy, as things were mostly written on top of each other) - you may decide how successful. Anyway, the last version of Mahler 1 is so much better than the earlier ones...