so you can still get the original Single-coil bridge pickup sound?

how do you determine which of the two singles (in the one hum) to make the active one?
you wont make either one active, you would just split it and have the inner coil (towards neck) tapered off so that you end up with one coil working independant of the humbucker... seriously, just take it to your local guitar tech, youre going to have to buy a new 4 lead pickup or have your factory one split and re-wired to have 4 leads. not something that having a little soldering experiance would cover
"insert witty somewhat racial, innapropriate, degrading comment here"
^It's not that hard to split it...the tutorial is pretty concise, I know other people have gone through it.

I say try it on your own, and if you mess up, and can't fix it(unlikely) you can get it done by a tech.
I'm not very active here on UG currently.
I'm a retired Supermod off to the greener pastures of the real world.
ahhh, yeah , i had forgotten i read that tutorial on here not too long ago....disregard my previous advise.
"insert witty somewhat racial, innapropriate, degrading comment here"
If it's a Fender Fat Strat, the 'bucker is probably four conductor anyway. Cause position 4 on the switch will split it anyway, making the north (furthest away from the bridge) coil active, along with the middle single. Which coil would you like active? You can use a mini toggle or a push-pull pot.
These go to eleven...