There are three recordings :
at Caen
at St Omer (at 3'45)
on the Scots (at 7'30)
Vierne requires a nasard on the swell. As St-Omer has its nasard on a non expressive division, I preferred to use only the swell octavin (with the flutes of course).
I fear I am not convinced at all by the Scots which, IMHO, terribly lacks charm compared to the two Cavaillé. Its (only ?) advantage is to show in full light the imperfections in the playing.
There is an Audacity patch near the end of the St Omer recording.
For the Scots, I used the first take as it came.