I'm based in DCA/IAD, so not really a Delta heavy area, and most of my business travel are United (IAD) and American/Alaskan (DCA), so I don't really have much of a chance to fly Delta. This time, I will take this flight to Incheon (Y fare), which is marketed by DL by operated by KE. I can get an instant Silver status from a trial/challenge. I'm planning to get the silver status and request for MUA, but other than that I think I can change the FF number before the flight and credit it to others right? I checked wheretocredit, and saw a two options that I could pick, one is to KE (100%), the other is VS (150%). Looking from redemption point of view, which program would be better to put this flight into? I have some needs for flights between IAD and asia (China, Japan mostly), KE actually offers the only one-stop itinerary between IAD and my destination in China (not PEK/PVG), and in VS, I probably have even more use cases, to europe and even to PVG (recently had a redemption IAD-LHR-PVG).

Guess it would make more sense to credit this to VS? Is it even possible to use VS miles to book KE flights at all? Or I'm missing other important points. Any insight is appreciated.