You sum up what I was trying to explain in a dedicated topic on another forum years ago: according to the capacitance involved, the resonant peak of a pickup can align itself with the frequential peaks OR dips of a loudspeaker / cab... and when both promote a frequency altogether, it can become
extremely irritating (even with much capacitance, actually). That's why trying various caps is so important.
Paradoxically, that's also why extremely low capacitance can lead a passive pickup to sound "hollow" and weak instead of pristine clean: if the resonant peak of a PU is way above the spectrum reproduced by a cab, a good part of its stenght is lost for music, so to speak...
Regarding the fuzz: if ever it doesn't sound to your liking, you can always do the same than with your PU's: add a cap between hot and ground on the volume pot of your fuzz and listen how it softens the tone...
