chintu
505
Hundreds..
Dufour initially produced some 200 plus Simplicity watches and most were consumed by knowledgeable Japanese collectors.
Perhaps another 100 or so could have been produced over time for those on the subscription waiting lists.
The Duality which used the concept of resonance, was however produced in the count of low 20s or so.
On the same topic of quantity, the Svend Andersen secular perpetual which was offered at Sotheby’s, carried the Sl.no.34 and so I would think that less than 100 could be out there. I also found out that the base caliber used in the secular perpetuel is ETA2892. And coming to think of it, only two other watches - the historic Patek Caliber89 and the Franck Mueller Aeternitas have the same complication features.
Coming to the HM1 of MB&F, the total of HM1’s would not be more than 200 in number including the ones released in Series of 2 sets of 10 limitations (the Final Edition) each in 2009.
Cheers