I believe that playing piano at a level where I could either comp two-handed, or play LH chords and single-line RH passages (very slowly) would facilitate my improvisation skills and working out things in new tunes. Many of the great jazz players could do this. I had have a few years of piano as a kid so I understand the keyboard but my technique is abysmal. How would I best come up so speed? I don't have that much time and need to be careful not injure my hands so I would rather go slow and not deal with weekly lessons. Should I take lessons sporadically from a jazz player? Is there a good book or website that covers this subject?