Personally for me it's more about the time of departure from the west coast than it is the airplane, especially in Y where they all suck. I do a lot better job of managing my jetlag when I leave the west coast as late as possible in the day and arrive in EU in the late afternoon/evening, where all I need to do is get to the hotel, get through dinner, stay up a couple of hours and then go to bed.
In Y or in J, I never sleep as well on the plane as I do in a hotel bed, so for me it's about getting through the trip and getting into that bed at a natural time of night on arrival.
Thus, I'd connect over SFO using UA930, owing to my own personal preferences.
However, with the new DL nonstop from PDX to LHR, in all reality I would take that (if offered on your travel dates). It leaves at 5pm and DL has the best Y experience (IMO) of any of the US majors, and it's nonstop. However, I think it's non-daily and originally it was seasonal ending in October, not sure if that has since changed.