Looking at redeeming miles for business class tickets on Vietnam Airlines ICN>HAN in November. Have plenty of miles with Amex/Chase/Capital One. Any sweet-spots or pointers would be much appreciated.
Sounds like this site is exactly what you need. Put in your route and see which Skyteam airline looks the best to you:
https://www.travelcodex.com/award-maximizer/
Not sure how married you are to only flying on VN, but for the route there are cheaper options in terms of mileage spent, though most would require a connection. But some of the Star Alliance options look better to me, assuming OZ has award space.