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.
Have you considered the Rothwell inline attenuators? A pair should be quite a bit cheaper than a DACT. The standard pair offers 10dB of attenuation. I have a custom 20dB pair that I would sell for 1/2 price.

With a digital voltmeter and a test tone from the M&K Pro web site you can calculate how much attenuation is necessary to get better volume control.