Earl the gain is NOT a volume knob, you just cant tell someone a percentage! And amps dont "handle" wattage, the subs handle wattage. The amp produces the wattage.
A pair of kicker CVRS want to see anywhere between 500-800 watts RMS.
The dual 2 ohm versions want an amp like the kicker zx750.1 or any reputable 2 ohm stable monoblock amp.
The dual 4 versions can use either a 1 ohm stable monoblock amp, or a 2 channel amp, since a pair of dual four ohm subs can be wired to either 1, or 4 ohms.
PS totally ignore the PEAK or MAX numbers! They mean ABSOLUTELY nothing, its pure marketing.