As for the tempo, I'm not entirely sure what to make of Gould's approach
here, especially in light of his expressed admiration of the third movement
-- although I like the tempo of the first movement very much, I agree that
the third seems a bit too fast. I tried to find some unifying relationship
between the three tempi in hopes that this might elucidate things, but had
little success, and am inclined to think that this was not a case in which
Gould carefully planned a single consistent "pulse" to carry through the
various tempi of the piece. But FWIW, here are the approximate tempi I
calculated (using a stopwatch to time the first four or eight bars and
calculating thence):
1. Adagio Sostenuto (4/4 time): quarter note = 74
*however, the ritard takes us to an ending approximate speed of
quarter=42