Calling all Aesthetix Callisto / Io Owners

I have owned an Io (standard version with 1 power supply) for a little over a year. I replaced all the tubes in the audio chassis with Telefunken tubes and this was a huge improvement. And this week I took delivery of a Callisto (signature with 1 power supply).

1: Since I also have another line stage here (BAT 31SE) I would like to try both of the Aesthetix power supplies for the Io to see if I ultimately want to go with two supplies here. I would also like to try both power supplies in the Callisto to hear what is gained over just one P.S. But I see that the power cables between the PowerSupply chassis and the Io have different pinouts than the cables used to the Callisto. Are the power supplies interchangeable or are they pinned specifically for either the Io or Callisto?

2: Are there tubes within the Callisto that significantly benefit from tube rolling?

3: Has anyone done a shootout between the Standard and Signature Io? .... and what were the differences?

4: On the Callisto, when I move the "Right Level" control, there is a slight crackle/static sound from full attenuation to the first step and then again in the next 2-3 steps. From then on the noise is gone. I have swapped tubes between the L & R channels, swapped power cables between L & R, tried using a different set of inputs, swapping outputs to opposite amp inputs, etc. The problem stays with the right side. Does the right level control need to be "cleaned"?

Thank you in advance for any input here.

John