Upload & Sell: Off
Hmm. I don't have the Zeiss CP, but Zeiss advertises the lens and it's filters working together. I've used a Marumi CP on the ZE mount version with no problems. I too want to stack CP and a ND, but that is problematic. Even with the thinnest CP/ND combo I can find, there is vignetting in the deep corners.
I'm planning on removing the ND from it's ring and placing inside the front threads of the CP, hoping I can avoid vignetting. I think there's a possibility that might work.