Hi, I have just installed a 4 channel power amp & Coustic XM-1e 2 way active crossover in my new car. I have 1 pair of RCA going directly into the Coustic crossover & then the high pass output going to the front channel of my amp to power my 2 way componets. The low pass is going into the sub channel of my amp driving 2 10" subs. How do I start setting the output levels on the crossover & amp? Do I set the gain on the amp first & then start from the lowest setting on the crossover slowly increaing that or do I set the levels on the crossover first & then procede onto the amp gains?