Slow jazz swing with acoustic bass, piano and brushes. The chords here are very different to standard blues chords, try to pick notes which fit with them. It won't be easy. It may help to try notes not normally used in standard blues, for example the half bend on the 2D (i.e. the major 7th). Also to devise melodies to fit with the mood of the backing, rather than wailing on a just a few notes. The (nominal) chords for the track in G are here.
Slow Jazz Swing in G
Slow Jazz Swing in A
Slow Jazz Swing in C
Slow Jazz Swing in D
Slow Jazz Swing in E
Slow Jazz Swing in F