Crossover Help

zero610

Can someone help me with the crossover settings for my system? I'm afraid I don't know as much as I should in this area. First off, what I have:

Fronts: OZ Audio 180CS (6.5 component speakers)
Rears: JL C2-350X (3.5 coaxial)
Sub: JL 10w1v2
Amp: JL 300/4 (powering front speakers and subwoofer)
Headunit: Kenwood DNX7140

My question is do I need to do anything with the crossover settings? There are crossover settings on both the headunit and amp. Is one set better than the other?

The amp has crossover settings for off/LP/HP and specific frequencies to filter above or below (based on whether you do HP or LP). Additionally, it has a slope to be set at 12dB or 24dB.

The headunit has crossover settings which are a bit more complicated. Phase for subwoofer (normal or reverse - whatever that means??), then frequency and slope for each of the speaker sets (front, rear, sub).

Do I use the filter on the amp and try to disable the one on the headunit, use the one on the headunit and disable the one on the amp or not use any/use both? Also, what slope do I use? Is that the same as the frequency filter on the amp and if so, what frequencies do I filter for HP and LP? Finally, the headunit manual says if I simply select the speaker size on the settings of the headunit, it will automatically select the crossover settings. Will that do it accurately?

Sorry for all the information and questions. As you can see, I need some help. Thanks in advance.