Originally Posted by tentseller

IME:

Since there is no complimentary upgrade on DL intl flights chance of EC seats opening up at the last minute is very slim.

Whatever EC seat you grab at ticketing is usually the one you will be sitting in.

SO
If you want EC seat then plan on not sitting together.
If you want to sit together then plan on not sitting in EC.

I can appreciate you position of not starting a vacation in physical pain/discomfort due to the long plane ride.