As another data point, I flew YYZ-LHR yesterday on the daytime flight and it was only 2/3 full up front and 1/3 full in back.
Ironically, it was one of the best crews EVER. Too bad so few were there to enjoy them and too bad the actual aircraft was such a mess. But better that than UA's 757 out of EWR for the daytime flight. No thanks.