Skip spence, you're probably not going to like
The War of the Jewels as much as you liked
Morgoth's Ring.
The Grey Annals and the
Later Quenta doesn't add up much to your knowledge, since most of the information extant in the published Silmarillion are derived from these writings (and from the Annals of Aman as well). Anyhow, it may be relevant to read the original writings in their entirety.
Moreover, there's also a long linguistic essay entitled "Quendi and Eldar", which probably is not interesting at all to the dislikers of linguistics (as you said you were
). The only "new" tale is "The Wanderings of Húrin", which tells the real story of Húrin after his release from Angband.
...
You guys are complaining about the price of the set of books, but in my country these books are even more expensive!! Luckily, I've got them all.