Again you wire at 2 ohms you will see around 300 to 400 watts after rise. Does none of this register to you? The sub laughs at 1200 watts from what kr15 says and it was in a larger side box as well. Youll want to 1 ohm the sub period. Not sure why you are soo hell bent on higher ohm load wiring., You lower the gain and sub level down and it will be a few hundred watts every bit as efficient and easy on your electrical setup as 2 or 4 ohms. The sub is beyond your conprehension in terms of power handling as well bud. Kr 15 ran it, he can tell you what the sub can do and what abuse it can take.
Also 40% or 60% gain means nothing. Gain is to match head unit preout. Not a percentage.