Slight Variations in the 12 Bar Blues Form - Watermelon Man Transcription
Due to the fact that we're not required to study scales and chords to play our instrument (at least at the basic level), playing to non-12 Bar Blues can be a great challenge. Many times the change in the form is very simple once you look at it closer. I've placed at https://www.facebook.com/bluesharmonica my transcription of "Watermelon Man." In this blues-based jazz instrumental you can see that Bars 9 and 10 of our standard 12 Bar Blues are played three times (the V and IV Chord) to make this a 16 Bar Blues.
When it comes to soloing, you can start by simply playing what you played for Bars 9 and 10 again for Bars 11 and 12, and then once more for Bars 13 and 14. Once you become familiar with the form you can get a little more adventuresome and plug in other cool V-IV-I licks from your Improvising Study 4 on the website. Jamey Aebersold has a jam track for this at https://itunes.apple.com/us/album/maiden-voyage-volume-54/id518527093
Special Note: If you have a harmonica playing buddy (or any other solo instrument) they can play the lower harmony part I've provided.