Firstly I will be working on the 6th movement which I remember well, but which usually receives a somewhat more relaxed tempo than indicated in the score. My question is what is the minimum tempo for the pulse to dance like a true scherzo? I must aim for a strict quaver = 100 or more, (where 70 is technically comfortable!) but semi-quaver quintuplet grupetti within indicated quaver of 132 will surely become grace note clusters; and using that more percussive technique loses the full harmonic colour of the musical layer. The first note of each group has to sing (mini accent) for rhythmic clarity, and the runs are to be even, soft and not splashed. I am informed by remembering the composer’s insistence that his 2nd Symphony scherzo was played at full speed, the Boston S.O. Musicians under Ozawa refused the ‘impossibility’ until a compromise saved its premiere, while the BBC philharmonic got a lot closer to the mark. Thank goodness the recapitulation is identical for the runs!