How should I wire 2 4ohm subs to this amp?

Wire subs for in series for total resistance of 8 ohms, bridge the amp for a final load of 4 ohms. This way it will be easier to tune the subs for output as you will only have 1 gain adjustment. You can also just wire them in parallel for a total of 2 ohms resistance, but you will have two gain adjustments and it will be harder to sync the output of the two subs.