I recently did WAS-ORD-YYZ-LHR... to take BA across the pond. Very good decision on my part.

Low/nil probability of getting award seats on Fri for TATL; push it up to Thurs. If later Friday does shake loose, you can freely change the dates of the itin. of a OW award (and I did so months after ticketing), just not the routing.

Better place for OW answers is the oneworld forum down in the alliances section.

Steve