Well since I only have 4 seats in a one row configuration I only did 3 positions. I did the middle seat and then the outside of the seats on each side. I didn't set a target curve so I will have to get to know the Marantz better so I will learn everything that I can do with it.
You always want to use the max number of measurements, so that Audyssey has the most snapshots or pictures of the room for the best cal it is capable of. Even if I had only one seat, Id do my 8, some people would recommend something like position, front, pos, back, pos, right, pos, left.
For yours, I think prolly 6, so once each for extreme seats, then one for
each ear in middle seats.
I will likely have time in the late afternoon to look around threads for possible choices/settings on your Marantz for target curves, but lemme know if/when you find them yourself so as I won't unnecessarily spend the time . . .