If you serious about using the drawbars, my reccomendation is don't get involved in the science...jsut learn to 'feel' the combinations. Treat the drawbars like a Graphic Equalizer with Bass - Mid and High frequences (and all the bits in between) and adjust as you the music takes you. Listen to some well known artists in the field of music you want to play and get the sound in your head. Definately don't overly concern yourself about number crunching! You don't need to understand the science to know Jimmy Smith used 888000000 or 888888888...you can just tell.