Thanks for your thoughts Phizzy.
The key word in Hebrews appears to be "better". I will keep Hebrews in mind if it makes a clear contribution.
As you say, by the time Hebrews was written, a High Christology had developed, as is evidenced by the Fourth Gospel, which was written by people who had been kicked out of the synagogue for that reason. ("Anyone who confessed Jesus to be the Messiah would be put out of the synagogue" John 9:22, NRSV).
Yesterday I received the book, "The One Who is to Come" by Joseph A. Fitzmyer, S.J. (which stands for "Society of Jesus", in other words a Jesuit priest).
When I scanned quickly through the book I was dismayed to see so many words written in Hebrew (I can decipher Greek letters ok but with Hebrew I am a disgrace). However, on closer inspection, I saw that Fitzmyer provides the English translation --- not in every case but it soon became easy to identify the Hebrew letters for the word "Messiah".
A good book. A really good book.
Doug