I cannot remember exactly, but it must have been
Hoofdwerk:
Prestant '8
Holpijp' 8
Octaaf '4
SuperOctaaf '2
Mixtuur Discant
Pedaal: all available stops, coupled to the Hoofdwerk
I listened to it again, indeed it is disturbing that the middle parts are `hidden' unless they are above c' where the Mixtuur Discant comes in. I did not used the Mixtuur Bas (which we often do not use in the Bovenkerk) because it is rather high pitched. I could have used the Scherp and/or Quint to mask this.
Well, I will make some new recordings using different registrations.