Hello Stephane,
the find-story is as interesting as the beads are magnificent.

Since you bought already 20 pieces from the (recent) "Mali-Morfias" - congratulations! - the value of the rest is possibly payable for more folks than the "serious collector" you mentioned, who wasn't able to identify them as authentic.

Maybe you can continue to investigate the true find-spot, since this would be of greatest interest. Must have been a true historic place of great significance.

More in private (though I am definitely not-not the "wealthy collector" you mentioned. There is proof I can deliver for this assertion: I saw immedeately those beads are as real-as-day!)

PS
Question:
Have you ever thought - or do you know - why especially Morfias are so valuable? They are nice, of course - at least those AAA-types you bought and are after - but there are other nice beads from the Islamic period that are less costly. Why, you think, Morfias have this special value in money and beyond?