Well, I finally managed to get this little project finished after trying a few different things and as usual the things that you stumble over are sometimes the best.
I really liked the sound of the Brierley pups and have to say they do have that genuine vintage tone about them however, I tend more towards a hotter sound and have opted for a second hand set of Seymour Duncan Quarter pounder split P's. In the bridge position I used an old SD Active J pup that I had lying around. The one with the 3 little rocker switches on it.
The mods ended up thus:
S/H MIJ Fender tuners & ferrules
Fender string tree
Fender nut
S/H Tort Pickguard
Gotoh 203 Bridge
Fender knobs
Gotoh 250kPots for Neck Vol and Tone
Dyna 100k minipot for the Bridge vol
Sprague Orange drop 200v cap
Switchcraft jack input
I had to extend the routing under the pickguard to accomodate a 9v battery for the Active J pup.
First time I've done a nut. I didnt file the string slots but got the bottom sanding to the right height.
The bass sounds great and has a large variety of sounds available to the player. It feels amazingly close to the genuine article in my estimation. I cant stop playing it atm. I was using it at practice last tuesday and a fellow musician that knew of but didnt know personally popped his head in the room and commented that it was "a sweet bass sound". I've had one guy offer to buy it and another ask me to put one together for him. The whole project including the cost of the original bass ended up at $240