Scott,
If you play the bass line, why not turn OFF the arranger? The kn5k will do that easily. Just split the board and assign the bass to the left and a chord sound to the right. Then just use the drums to finish the sound. It's very refreshing - especially in a more intimate setting.
Try a sipmle swing tune that only uses a few chords (Rt 66???) and walk your way through the changes. It comes as second nature after a very short time and you regain total creative freedom over the arrangment. You are the MASTER, not just the conductor. Try it!