elmo7sharp9

I don't see the other pickup interfering with the driver

I've maybe presumed too much ...

You know you'll need to remove the fine pickup wire from the "driver" bobbin and replace it with 100-200 turns of far thicker wire to make a practical driver coil, don't you?

You can't (easily) make a sustainer using a regular pickup coil as-is.

I don't see the other pickup interfering with the driver because it would be wired to when the driver was activated, the signal would be taken directly from the bridge pickup, regardless of the position of the pickup selector. Any advice or input? All is appreciated.

You've got enough physical space to wind a driver in this way - no barrier there.

The "pickup" coil of your humbucker will have an induced current from the "driver" coil

that may or may not cause resonance/squealing/fizz effects.

The simple solution is to short out (and, if that is not enough, disconnect the ground wire) from the "pickup" coil

during Sustainer operation.

Incidentally,

Your choice of .010 to .052 strings guarantees that you'll get far more sustain out of the lower strings than you can achieve on the top strings (when compared to a lighter-bottom string set).

For the moment, I've learned to live with this, as these string gauges are vital to the feel, tone and tuning stability of my guitar.