If you really want to get a TRUE handle on the jump blues style, it's very important to not just listen to harmonica alone but more so to real jump blues horn players like Red Prysock, Hal Singer, Jimmy Wright, Willis Gator Tail Jackson, Earl Bostic, and Joe Houston as examples (btw, many of the West Coast harp players and also Little Walter listened to this stuff as well) and incorporate it into your playing.
Also important is to listen to the jump blues guitar players as well, such as Bill Jennings, Tiny Grimes, T-Bone Walker, Pee Wee Crayton, early Gatemouth Brown, early Johnny Guitar Watson, Gene Phillips, Johnny Moore, Oscar Moore, or some of the more modern day jump guitarists like Junior Watson, Duke Robillard, and Charlie Baty as well.
It's also extremely important to learn how they use dynamics in their playing as well. ---------- Sincerely, Barbeque Bob Maglinte Boston, MA http://www.barbequebob.com CD available at http://www.cdbaby.com/cd/bbmaglinte