panning is preset base. It depends on whaich algorithm you are using. Those offering a PAN parameter will also give you the possibility to patch a CC to it.
The manual has a detailed section about how to assign any controller to a parameter.
As far as level, well…2 channels will always be louder than one. When the signal is in between the 2 extreme L/R positions, its level is obviously changing as this is the way panning works.
all the best