Bass is my main instrument but I've never used it for playing Shads.
I'd suggest however, set the volume on low to medium, then put all the tone controls to the 12 o'clock postion (flat).
Have a play and see what you think. If not happy, just make small adjustments on each separate tone control and see if that gets nearer to what you think, a Shads bass sound should be.
good luck
