^ Put mic #1
at center seating. Pick the other 4 positions such that:
1) The mic positions span the listening area you want to correct -- both side to side and front to back,
2) Each subsequent mic position in sequence alternates from one side to the other of #1
3) The mic positions are not all at the same distance from the screen -- for example have some set up near the back of the headrests and some at the front of the seats
4) No two mic positions -- whether or not sequential -- should be set up closer than 24 inches apart. I use 30 inches as my minimum.
5) The mic tip is not set closer than 18 inches from a blocking or reflecting surface like a wall or high seat back. If necessary raise the mic tip a bit to clear a seat back, or shift the mic position closer to the screen to get distance from a wall.
6) The mic tip should point straight up towards the ceiling. The mic tip should be set at seated ear height for all positions (adjusted as necessary for rule (5)).
The mic hears audio from the entire hemisphere -- 360 degrees around -- above the tip. So that's the area you want to keep clear of nearby things that block or reflect the sound.
Here's a pattern that should work for you: