amp install question with factory head unit

[22bayranger]

I want to install 2 amps in my 2013 f250 and retain the factory stereo with nav.One is a mono block with no line level inputs and the other is a 4 channel with line level inputs.What would be the best way to go bout the install?Should i use a Audio Control LC6I to provide the signal to both amps or utilize the line level inputs on the 4 channel and buy a cheapie LOC for the mono amp?Thanks.