Pierre, I have checked this, the wind pressure on which this stop speaks is 110 Mm.
It is on Manual 2 (Schwellwerk), all the stops of this manual speak on 90 Mm, except for the two reeds and the Syntematophon, which are on 110 Mm.
Regarding the history of this very interesting organ: there is a book available called "Orgelreform in Nederland:, published by the Walburg Pers / Stichting Monumentaal Walcker-orgel Doesburg / Rijksdienst voor de Monumentenzorg. It was published in 2003 and is still available, if you are interested.
I know the organist of the church very well, so if you would like to visit the organ (and see the inside), this is possible. Please let me know, I can arrange a visit for you.
There are also several very interesting recordings available of this remarkable and truly monumental instrument.
Some pictures of it can be found on the following link:
http://www.xs4all.nl/~twomusic/concerts/Do...g/Doesburg.html
regards,
Dave Lazoe.