Ba268 pax re the "southerly route" I came out of SFO a day later our route took us just north of Denver, over ORD across lake Michigan then due north of Grand Rapids and Toronto finally making Oceanic just to the NW of Gander.
The winds that night were much more favourable at this latitude than going further North towards the pole and Churchill/Yellow Knife, looking at the sig weather chart it "appeared" that the jet stream we used had been at this latitude for a few days, certainly since we had left LHR for SFO 2 days before.
I thank you for your honest and open account.