Lawrence Kramer's book on poetry and music in the 19th century seems promising. I first came across his work in a book on John Ashbery, edited by David Lehman I think, called Beyond Amazement, where Kramer analyzes Elliot Carter's setting of "Syringa." I must have read this as a teenager.
The prose is very high-theory 1980s. The connections he find are sort of allegorical, in the sense that they derive from very convoluted musical and literary analyses, and then comparisons between these convoluted analyses. I would like to find more direct, intuitive connections, that don't depend on a musical ear that can hear Shenkerian analysis.
I've spent a lot of time worrying whether I can do this project, but I've decided to do it so too bad if I can't / am not qualified. I've certainly found a not so great book with the subtitle "FGL y la música." I am already at a higher intellectual level than this guy.