I remember very well, working the expression pedal on my B-3...a necessity for me.

That why I say...you don't play a B-3...you ride it.

The Leslie was just as much a part of the expression, and to know when to switch from slow to fast was an art...between the swell, and the half-moon Leslie switch, it was like playing a voice; a human-like voice, with tonal, and volume expressions from the drawbars and swell pedal, to the pseudo vibrato from the rotary speakers winding up and then down.

You could make a note seem to "hang" by stabbing at the expression pedal.

Ian