Re: 59N Problem...
I had the exact same issue you had, especially because I have it paired with a JB bridge. And I have found a solution that works great for me. First I swapped out the A5 for a ceramic magnet, alot better but still heavy on the bass but because it's much tighter I could live with it. Then I decide I wanted it to be a little hotter so I sticked the A5 on the bottom plate of the pickup together with another ceramic magnet. Not perfect but great non the less! Became a lot more crunchy and tight under distortion and still stays warm and clean when played clean.
I also tried to rotate the pickup in the cavity 180 degrees so the polepieces face the bridge. This worked very good for taming the bass but the tone gets a little weaker and the low E string was suddely much lower in volume compare to the other strings so I reversed it back.
You could try it to see if you like it, it's the easiest thing to do and to reverse if you don't like it.
Good luck.