in need of some advice, 1994 saturn sl2

I am currently in the process of building the system in my show car. its a 1994 Saturn Sl2 I have removed my back seat and i am replacing it with a custom subwoofer box. I have installing 2 dual voice coil 12s and a single voice coil 12. I am trying to figure out how to wire them together to a 1200 watt mono rockford amp. I know how to wire the two Dual vocie cooil subs but i am running in to trouble with intergrating the single voice coil and getting it to sound right. Any advice would be much appreciated.

It would help if you could tell us the impedance of the coils on each woofer, and the lowest safe operating impedance of the amplifier.

i believe the two dual voice coils are 6 Ohm and the single is a 5 ohm The amp i am not 100 percent on I will check today and post it tonight when i get home from my shop.