Ok, I managed to get the CV working with the Factors straight from the MP201 by changing the Heel, Toe and initial values of each channel. It is a bit of a pain setting them using the rotary encoder but using UTILITIES > COPY/SWAP PRESETS in the MP201 speeds it up massively (I wish I found it earlier!)
The responsiveness seems excellent, certainly better than MIDI CCs. I just need to get my head around all the implications of the LFO parameters to make full use of it and I will have a look at modulating multiple parameters at once to see if this responds better than MIDI (that certainly was quite laggy when I tried it using CCs).
Now a question to the eventide peoples: I want to try and get my H8000FW working with CVs too, in the user manual it says of the foot pedals: "Each foot pedal jack accepts a stereo ("tip-ring- sleeve") 1/4" connector (see diagram below). Between the ring and sleeve is a fixed 5 volts provided by the H8000FW. The foot pedal that is hooked up to the jack and returned between the tip and the sleeve alters that voltage." So can someone confirm: does this mean that I can use a CV input of 0-5V as expression pedal? and more importantly is there similar "protection circuitry" that prevents harm to the unit if CVs outside this range are sent?