Figured out a workaround for the Performance Switch assignment for the Rotary Algo using my Helix:
Posting this in case it’s helpful to anyone…took me most of the day to find a workaround 
🙂
I was trying to figure out how to use MIDI CC from the Helix to control the Performance Switch in the Rotary Algo on my Eventide H9. I could set up a MIDI CC toggle switch and map it to the Performance Switch function, but when I do that – instead of mimicking the Performance Switch 100% (Fast/Slow; hold for Brake) it would only toggle between Fast and Break.
BUT – if you assign an expression pedal as MIDI CC controller to the performance switch…it works. Toe down is brake and heel down toggles between Slow/Fast. You can use Min Value 0 and Max Value 127 for full range, but it seems to feel a little better to me if you set the closest possible max/min values for on/of (63 & 64).
What David Lynch would call a “happy accident” because I kind of like working it with the expression pedal better than hitting a switch. A little more like a real Leslie.
Now…you might ask, why not just assign max/min rotor speeds to the expression pedal and skip the performance switch function altogether? Because it doesn’t ramp when you do that. I just glides in between fast and slow and in a rather un-Leslie-like way.
