Battery Lead Wire Gauge

For correct wire size consult the winch user manual. If too small of a wire diameter is used, the wire may overheat and become a fire risk. 

To avoid overheating (motor and/or power wiring), the winch is designed for intermittent use, allowing it to cool if it gets too hot.

Wire gauge vs acceptable amperage would be for continuous use or other applications that don’t correspond to the intended use for this winch.

Gear ratio is just the mechanical reduction in revolutions from the motor down to the drum and is not related to wire gauge. Basically, if the motor spins around 1800 rpm, and the gear ratio is 432:1, the drum will turn at just over 4 rpm, but what it loses in speed it will gain in torque or pulling force.