Sub Wiring Question

Getting to the end of all my projects, yesterday I installed my new sub box and went to wire it to the amp.

The sub is an 10" Alpine Type-R (SWR-1042D) which is a dual 4ohm voice coil sub. The recommended power (RMS) to the sub is 500W with a peak of 1500W

The amp I'm pushing it with is a Cadence Z4000 amp which is capable of providing 2 x 300w at 4 Ohm Bridged Power.

The way that I have the sub wired is I've run one set of voice coils in parallel (+ to + and - to -) inside the box and have a single +/- coming out of the box to the amp.

My question is what would be the way I want to wire this?

1. Do I run the amp in 4ch mode and bridge channels 1&4 (+ to ch1 and - to ch4)?
2. Do I run the amp in 4ch mode and bridge channels 1&2 (+ to ch1 and - t0 ch2)?
3. Do I run the amp in 2ch mode and bridge channels 1&2?

HELP!!!