Try it on a cheap pup first.
Or do like he suggested and buy a used one(or two), mod those and then drop em in.
I was kinda like you though, I wanted that Peter Green mod pretty badly...fortunately for me I was able to find a video walk though of a guy flipping the magnet on a very expensive OEM PAF that had been out of phase from the factory...that video inspired enough confidence that I was able to do that delicate of a job FIRST time, first try.(BTW mine wasnt a PAF)
My advice is to try it on another less expensive pup...I was too anxious and couldnt wait to find a donor.
Oh yeah, and look for a How To Video online!
[edit]But if its already a 4 conductor pup...then rock n roll...break out the soldering iron!:rockon: