Hi Guillaume,
That’s great you have the transcribed the first solo. Try to play it along with the recording exactly as Wynton plays it and then move onto his next solos.
Step 1: Focus The Rhythmic Placement
When Wynton is comping behind the other soloists, first try to work out the rhythmic placement of his comping voicings.
Next listen to his dynamics, is he stabbing the chords? or holding them down? perhaps he does both.
Pay particular attention to which beats in the bar he places his comping voicings on.
Finally, notice how much space he leaves for the soloist.
If you are playing in a jazz band, most of your time will be spent in a comping role, and so studying how players such as Wynton Kelly comp is a very worthwhile exercise.
Step 2: Transcribing The Chords, & The Chord Melody
Firstly, as a disclaimer, transcribing voicings note-for-note is difficult.
Try to work out the note he is playing on top of his comping voicings. That top note is the clearest note and you should find it easier to hear that note over the rest of the notes in the chord.
You will also hear that his top note moves around, ie. he doesn’t just comp with the same note on top throughout. This subtle movement is also known as the ‘chord melody’. Pay attention to that.
The changes for “Phrancing” are the jazz blues for but with Ab7 in bar 8 and a Db7 in bar 9. You could also imitate his comping rhythms and apply them to the changes in a regular jazz blues form.
I’d recommend first playing along with left hand voicings to imitate the rhythmic placement, for me, that is the most important thing to absorb.
Then try to work on the top note of his comping voicings ie, the chord melody, and finally try to fill out the notes in between the left hand voicing, and the chord melody note.
Here’s some lesson links you may find useful: