Economy will be 80K per person round trip, so you'll need a bit more. DL is running a bonus on mileage purchases and transfers right now, so transferring some miles from a friend or buying the few extra you'll need might not be a bad idea. Call DL and inquire about availability on China Southern (CZ) or China Eastern (MU). Both are showing availability for your exact dates in economy on ExpertFlyer. I might try for Korean Air (KE) first, but you can't check that online at all, so DL agent will have to check it for you. One benefit to KE is that you shouldn't have to pay the fuel surcharge, which you will for CZ and I think MU. You might have to prod the agent to long sell the award if they don't see the partner inventory.