I currently use my customized Fender MIJITSO Jazz as a main bass. Though modified it still has the tone of the Jazz and it's very easy to play. It's strung with D'Addario XL roundwounds, my favorite strings. If anything, I would catagorize these as being biased a bit to the bright side but with plenty enough bottom my ears. Recently I practiced steadily with my Kawai that is also strung with the XL's and found that I liked it's higher string tension over the Jazz. My rather loose style was given a boost by the more responsive action. So the question is: From your specific experience with the Jazz bass, what would be your recommendation for a high(er) tension string in the roundwound variety?