I've attempted to associate Tengwar-like symbols to English phonemes in a way that makes more sense (to me, at least) than the association Tolkien created a couple of times, but I never wrote anything down and it was too much information to keep all in my head, so I never got very far.
I also came up with a way to represent numbers in base 16 using Tengwar-like symbols. Because hex is so much better than decimal...
NICE
Yep!
Have you ever looked at the pronunciation guide and symbols in any dictionaries? Referencing in particular something like the Shortened Oxford Dictionary, which has a whole thing at the start dedicated to it.