I was doing the same thing,  5 min goes by way too fast…

I has some successes with this; allthough I was using a guitar so…

I’m working from memory so bear with me:

1^st make sure all 2^nd LFO are off, D mod & s Mod to off or zero.  This is so you can get a good basis feel for the algorithm.   Lower intensity to about 4, Set Modulation Depth or Vowel Sound to WAHWAH.  very important, Turn tempo off,. Lower Modulation Speed to 4 for 5 , And set Modulation Waveform Shape to Envelop [ENVLOP] .. 

Note I have to lower overall output to -5 as the single was real hot when I hit the strings hard.

That should get you a basic auto wah.  I believe the Modulation Speed will be a sensitive parameter on most auto wha so use that to find the sweet spot on your attack.

Then you can try different Modulation Depth like bass wah to see what happens.

Hope that helps.