Using a DACT pvc between my preamp and amp?

Hi, I am thinking about adding a passive volume control like a DACT CT2 between my preamp and amp to help give me more range in volume control. Right now, at volume level 2 on the preamp the sound is fairly loud. I want to keep the flexibility of a remote volume control via my preamp so I thought putting a pvc inline between the pre and amp to attenuate the signal enough to give me more range of control.

That being said, can anyone let me know what I should consider in terms of impedance of the DACT pvc? They sell 10k, 50k, and 100K ohm versions. What version should I get? From what I understand, I want the input impedance of the amp to be as high as possible. Does that mean I should get the 100K version? What does adding a pvc do to the amp's input impedance?

By the way, my preamp (ARC Ref 3) has an output impedance of 600ohm and my amp (Pass Labs XA160).

Thanks in advance.