Pot value reactions to EQ

[valve]

You're basically right. The pot values don't just control what the highest frequencies are that can pass through, they impact the resonant peak of the pickups as well. A lower pot value will place the resonant peak of the pickup a bit lower on the spectrum.

This is a really crude drawing, but it's sorta kinda what's happening:

That's actually wrong!
the pot value just loads down that peak, the resonance freq is still the same!
a higher capacity (like a longer cable) will do what you sketched

 

[valve]

Taste changes over time. I was into a more scooped sound. Then a thick raw wall. Followed by a brighter sound. Now a more refined punch and thump.
I usually end up with a 500k. Even with ceramic.

sounds familiar!
i am at stage 3