Hi ! 4th position is excellent for gipsy swing as you have easily the harmonic minor scale (3'' 3 +4 4 +5 5 6' 6). I just recorded really quickly an improvisation on Swing Gitan (in G-, played on a Bb harp) :: https://soundcloud.com/s-bastien-fr-mal I began jazz 6 months ago, it's still a little messy. Sebastien