I think that adding a tone pot at the value of 250 will darken it quite a bit. You could use a higher value capacitor as well, but soldered between the volume pot and the the tone pot.
Ola Englund likes Bare Knuckles Pickups, and he is really into the Aftermath, but he likes the Duncan Distortion to a greater extent. Which brings me to this next statement; I don't believe in certain pickups being better than other pickups. Yeah, there are pickups that are made out of better quality material, and are done by hand, with much attention and care given. But that doesn't mean that it is better necessarily. I think that beauty is the heart of the beholder. In the end, sound is sound right? I read this on the forum, and I will quote it now, can't remember the author of it but; " If it sounds good, it is good"
I am totally into BK pickups that I have used, but there are other pickups that I also enjoy, and think sound really good. Us humans tend to get caught up in bias, and what other people tell us is cool. But lets be honest, an artist can make anything work. Yeah, it helps to have the most awesome tools, but allot of us are rather feeding some form of addiction with our geariness. I have been guilty of doing as such. I can be honest about that.