CHN's best option is to kill some speed and let the pinwheel go by - round close to the mark and try for a high lane (clear air). Tack away if they can't maintain clear air.

RUS, FIN, NED are screwed - on the outside of the pinwheel.

GRE has an option to jibe and try to cut in behind the pinwheel, but CHN may prevent it if they jibe along with them. They are not within 2 BL of the mark, but they will be almost as soon as they jibe.