Thanks. that's what I was looking for.
I must say, the I flew KE last year on a cheap ticket and while I couldn't reserve any seat beforehand, even after an number of calls to Delta, who said they would try, at check-in, I was able to get a good exit row seat, which is all I wanted in the first place..
I'll probably go with KE SFO-ICN-SGN since I do like the KE economy seats and service.