I know there's a thread on this matter. Just so you know.
I'd like to run an experiment on this matter using some typical configurations (caps as HPF, caps as LPF, caps as power decoupling, etc.).
I just shipped some of my stuff to China as I'm moving back to China, so I won't be able to test them now.
But I will make the final move by the end of November, so in a month I can do the test.
In the meantime, post your ideas and caps you'd like to test. I'll test them in the near future.
I'd appreciate if someone has some really niche ones to test (like some NOS or fancy ones), as long as you can ship them to me before I leave. PM for me address.
BTW, if you have an amp or something that you'd like to test, I'll be happy to test.
Gear: Keysight M9260A with new, binned DAC, -122dB THD on best channel combination.