roussel2nis Oh, unfortunately I have to disappoint you. So far, the sample set is only available for Hauptwerk. Joseph Basquin does intend to do a Grand Orgue version of this as well, but I'm afraid that will take longer.
I had obviously checked that GrandOrgue was supported on his website before ordering.
Fortunately, I sent him a mail and he provided me the download link for GrandOrgue.
So far I see that the other samples from him are also available for GO!
I don't know since when it's available in that format(no announcement) but I think it's recent.