Do you have small speakers that you would need a higher crossover than 80-100hz? Even if you have some bigger speakers you shouldn't set them to a lower crossover.
Multipiont vs. single point can be debated all day. Simply, with single point you get great sound in one spot. The closer you are to that spot the better the sound will be. Multi-point will give good sound in most seats but not great sound. You can't adjust levels, distances and EQ to be accurate at every location in your room, it defies physics. You can either pick one good location or make the best compromises between multiple locations.
Also, EQ can not correct poor seating, speaker or sub placement it can onlky compensate somewhat for it but it will never be as good as if set up properly.