Silmarillion: What would you add/expand?

[Aiwendil]

So, my next question is, Is there any text or set of sources which separates CT's work from JRRT's work? The Silm project here, as I understand it, attempts to integrate all of JRRT's drafts into a definitive or authoritative text. My question goes in the other direction. How can I find the original fragments of The Silm before CT created his palimpsest?

In The History of Middle-earth. There, CT goes through the texts very thoroughly, even noting many of the places where he made editorial insertions, and explaining and correcting some of them.