I’m well acquainted with Gurdjieff and “the Work”. Though I’ve never managed to make my way all the way through Beelzebub’s Tales (and, yes, I realize there are those who will tell you this means I’ve missed the essential), I have read and reread the books of Nicoll, Ouspensky, and the other writers you mention a number of times.
There are many good things to be found in these teachings, but I believe very strongly they remain all but inoperative outside the initiatic and sacramental context of the Orthodox Church. As you may know, Gurdjieff is reputed to have told his disciples, shortly before he died, that they should go to Mount Athos. Whether this is the case or not, it’s certainly true that many of the most important elements of the Work are to be found in the teachings of the Hesychast fathers. An interesting (though most uneven) book on this subject is A Different Christianity by Robin Amis.
In turning to Orthodoxy, you would lose nothing of what you have found in this modern distillation, while at the same time you would gain something the Gurdjieffian system does not provide: access to the “uncreated energies” of the sacramental Mysteries and an unbroken tradition of contemplative prayer that still bears the fruit of deified men.