I would disable the WFCO, not remove it but Disable it... Two ways to to do this
The Best: There is a breaker most likely labeled CONV. Turn it off and insure that it does not "Kill" anything else (IE Bedroom outlets) Remove the wire from it and either tape or wire nut it off (I'd tape Install a new wire (12 ga Romex is my choice and if it is a 20 amp breaker indicated 14 is ok for 15 amp breaker) from the breaker to an outlet box you install where you are putting the Progressive Dynamics unit. (or a junction box if it's hard wired)
That way if the PD fails you can just re-connect the WFCO
Other method (not as good) Turn off breaker and tape or otherwise "lock" it off (They make a breaker lock device you can get)
But I like the idea of unhooking the wire that way the WFCO is not accidently engaged.