To the OP,

The DL.COM website will be useless for you. You can try it, but it will only show the flights on Delta (not all the partners). These are almost always very expensive.

There are several other airlines that DL can book you on that will be much more reasonable in miles. BUT, you have to call and ask. Sometimes you even have to suggest the airline and route.

Most consider Korean Air the best choice if you can get it (I have done this twice). But if I could get a ticket on any of the China airlines I would go ahead and do this.

The only way to get it done is by calling Delta. I have found the international award desk fairly decent, but it still helps to know what your options are.