Still trying to get that 3402? The H510 is better.
Anyway....
The front speakers and subs should have priority. Do all the steps like I mentioned. Keep the rear fill off the whole time. Once you have the whole system sounding as good as you can without the EQ, then plot your speakers in car response. Depending on the curve you have will decide how you should divide up the EQ bands. If your lucky you may only need 4 bands for the front 2 channels. Then you can use the other 3 bands for the rear fill. If you need more than 4 bands to do up the front speakers and sub properly, then set it up so that all 7 bands are on the front speakers/subs.
How is your signal divided? Are the subs running off the 2 front channels and the rear fill running off the 2 rear channels? If not, that's how I would recommend doing it. Let me know if that doesn't work for you.
Typically you will end up with most of your bands focusing on the under 300Hz region as it's the most troublesome area. Once you get the main speakers set up then you can turn on the rear fill and set their volume level and see how well they integrate with the main speakers.