Thanks Paul. I have a pretty powerful stereo in the back, and intend on upgrading the alternator to the later 120a 3g spec from a 94-95 MTX. Hence the 4awg.
I had a look briefly last night. The first stop for the BK/O is the starter solenoid on the driver's side fender apron. Unfortunately, it seems to continue on from there. There are two rings with BK/O wires on them, and both have fusible link on them.
I'll likely throw at 4awg with a 130a fuse between the alternator and solenoid and leave all the other wires intact.