You might want to look at connecting through LAX if you want to stay with OZ/UA. There are two OZ flights (OZ201 and OZ203) at 1200 and 2300). OZ201 gets to ICN at 1735 and OZ203 get in at 0420. The walk at LAX is a little longer with a trip into the tunnel along with the construction at Terminal 4 along the way being a minor issue. Clubs are similar (UA T7 and *A in TBIT) at LAX with the SFO clubs. Another possibility is going through SEA which leaves IAD at a decent hour and gets to ICN at 1745. Only issue at SEA is there's no real way to walk to the South Satellite but the train isn't too bad.