Hello Findegil. Now I come to this thread and after so long I am going to answer about what I think and what I always worry about. I think the solution is correct based on what you had explained in detail above. It is a wording similar to the one I developed after the discussion. But in the meantime the famous text "lost" for the public in an auction "Concernig .... The Hoard" enclosed by him in a 1964 letter to Eileen Elgar (together with Kinship of the Half-elven) came to mind. According to Cristina Scull the story closely follows Q30 with some differences: for instance, before beginning work on the treasure, the dwarves agree to accept a payment of a tenth of the unwrought metals. Thingol, however, is still killed outside Menegroth, with Tolkien giving two possible reasons why the dwarves were able to pass the Girdle of Melian.
http://tolkiengateway.net/wiki/Conce...27The_Hoard%27
Have you thought about this?
Greetings