I don't know if this will work for Jessica, but it does help with the stuff I do. I have the interval set to a third, then have the expression pedal programmed to change the interval between a third and a fourth.. this helps pick a more musical harmony depending on which note of the scale you are hitting. say you are playing the fifth of a scale and press the pedal down to fourths will get the fifth plus the octave on top, instead of the fifth with a 7th on top.

If eventide ever implements a user defined scale (a la H3000) this would really be a breakthrough for intelligent moving harmony.