Re: spliting pickups from hum to single
The stronger the output of the bridge humbucker the better it'll sound split.
The DC resistance will give you some idea.
Pickups with a 14K - 16K DC Resistance tend to be higher output pickups: Custom, Custom 5, JB, etc.
Of the bridge humbuckers with high output that have good tone when split, I like the Duncan Custom best. I also like the JB but only with 250K pots, because 250K pots tame some of the aggressive treble of the JB.
Bridge pickups with a DC Resistance of 8K or less tend to sound weak when split into single coils.
Neck pickups with a DC Resistance of 8K or under tend to sound stronger when split into single coils because the string itself moves a lot more over the neck pickup and induces a stronger signal even though an 8K humbucker is only 4K when split into one coil.
In dual humbucker guitars with 500K pots, I've had great luck with a PGn and a Duncan Custom, and the split tones sounded pretty good to me. I felt that the split tones were best when the two split pickups were combined in the middle setting of the selector switch.
But this thread is about S/S/HB guitars. Most have 250K pots and the JB sounds better with 250K pots than it does with 500K pots...so how about trying the 16.6K JB? You'll have a 8.3K single coil when the JB is split.