I’m on the west coast as well and it pains me the few times I route thru the east coast. The LAX-LHR and DFW-LHR AA flights are the best, lengthy enough to sleep and no crappy east coast weather and air traffic to deal with. Not sure on your dates but there is a new LHR route starting up in the future, LHR-PHX i think? But if i go thru the east coast i invariably take the daytime flight to LHR, and have found it can have decent Y-C upgrade space. Also, dont forget RDU-LHR, folks have told me that is a solid one for Y-C SWU SWU upgrades.