Douglas, check your e-mail.
There are many ways to approach this subject.
Mine is:
Reduce evry chord in the song to it's simplest form. C7-9 = C7 Fm9-5 = Fm
G13-5+9 = G7 ECT--
1- Now it's very easy to memorize. Also very easy to find familiar progressions.The first time I saw the sheet music to the song More, I was able to play the song without the music. There are two types of progressions in the song and I knew them both -- ala, no music needed, I knew the melody.
2- Because I have learned the basic of chord subsitution, I color the song as I wish. The progression of chords should tell their own story, they should sound good by thenselves.
And of course the song has my own personal flavor. Is this hard to learn? No. Is it worth spending the time learning? Only if you love music and wish to spend time enjoying.
All in my humble opinion, John C.
PS,I use the original chords only to understand what is being said.