Korean Air Skypass - KE economy seating

I've spent an hour trying to find info on this question, but I'm batting zero.
I'm flying economy tomorrow from NRT to LAX. KE says there are 50 seats available. I don't mind the back, and I'm wondering if asking for a seat toward the back in the center aisle might maximize the chances of empty seats next to me. Could someone please point me toward info on how KE, or airlines in general, assign seats? With so many empty seats, is there an advantage to checking in late, I mean because I might have a better shot at empty seats near me then? Any info would be greatly appreciated. Thanks much.

I recently flew to Asia and selected seats in the back for the same purpose (I also hate waiting for everyone to unload their luggage when deboarding. I would rather sit and read.) I my experience, there were more empty seats in the back. It looks like they also purposely left the very back seat empty. Sometimes the loo can smell which may or may not be a nuisance for you.

Well, just FYI, I did get 4 seats in a row toward the back and was able to stretch out. But I'm not sure if that had to do with my theory about the back and late check-in, or more to do with the fact that KE seems to give a lot of consideration to frequent flyers like me. Maybe both?