It will take some time to optimize choices. (sigh!) I will miss open seating, but there's no looking back. It will be a completely different strategy.
DH has ALP for next year so we can choose any seat. I am not sure we want the ELR seats because I figure they are the most likely to be 100% filled up-even the middles.
We can't do the window/aisle combo (which we pick with open seating if we know the aircraft is at least 50% empty). The LUV seats are going to the way back on the 700s.

If our desired seats are not available (in the open seating model), we take the row right behind the exit row--it is often the last middle seat to be taken. But, that is all out the window now because under the assigned seating-- if you book a choice fare -that is the first row you can pick as far forward of the plane as possible.

I have been toying with the idea of aisle/aisle (across from each other) in the ELR rows as far forward as possible (but not the first row). It's not like we can talk with each other
on the flight. Or, maybe LUV seats on the 800s.

I booked Luv seats for a couple of flights on 700s in March of next year. I guess we might have a seat mate.