As I recall it, most of the SK flights were less than midway and did a u-turn. I know I saw pictures of some inflight maps with the u-turn, but I am unsure about the number of flights. The east coast flights at that time departed more or less the same time back then, and SEA would still have been on the ground in CPH or just left CPH when the airspace closed. It left just around the same time as SK983 if I remember correctly.