That would be me, Paul..!
Way, way back in the 1890s (yes the decade of grunge) I did some impedance plots of some passive guitar pickups I was studying. I discovered that a typical dual coil "humbucker" had an impedance of over 160kΩ at resonance (which was around 3.2kHz). In terms of impedance matching this explains why low value pots can reduce the "brightness" of a guitar pickup - they act as a zobel of sorts and damp that resonant peak.
Of course that is when the pots are full up... I think I was referring to DC measurements on the pickups. Maybe not, It was even before the 80s...
Here's a good one:
Everyone knows that Eric Johnson can hear the difference between type of batteries, which is easily explainable. He could also hear that the 5 position switch was darker than the 3 position switch in a Strat, when stuck in the middle between T pickup and M pickup. It was actually quite clear, until I figured out why.
When Fender made the wiring harnesses, one wire looked slightly short, so to get it right it had to be tugged on a little. This wire was connected to the Middle tone control, and cause the contact to rotate ever so slightly. Of course, when switching between the 3 pickups, the T pickup had no tone control, and the M and F did. When switching it into the middle position between T and M to get both, the contact didn't quite touch, disconnecting the M pickup's tone control. This made it every so slightly brighter. When the 5 position switch was made, they made it "correctly" and the M tone control was in the circuit in that same position. Snip that contact and you have the original...
But wait, there's more... Aside from Jimmy Hendrix stringing his guitar upside down, effectively slanting the T pickup the other way, he also swapped the M pic-up and F pick-up on the switch, so it went T-T/F-F-F/M-M, so his sound was a combination of that angled pickup and the F and T pick-up in parallel, with no tone knob.
BOOM