sweep to back only using the fader and then from left to right using balance to see if you have any duff channels if not how you set it is entirly up to you so even if you get a setting from someone else you mght hate it.

I would have most of the bass to the rear as imagine they are bigger speakers and to the front i would have higher end as they are more lilely to be swamped by road noise.

Best bet drive out to somewhere quite and spend a few hours twiddling