As far as which is least profitable, I would see which route to NRT has the most Low award space in BE available.

Checking low BE dates over the next two months:

PDX - 18 out, 8 back

SEA - 9 out, 11 back

SFO - 31 out, 12 back

LAX - 40 out, 10 back

MSP - 51 out, 26 back

ATL - 47 out 28 back

JFK - 45 out, 42 back

So, it would seem that PDX and SEA are the tightest for award space, which would indicate they are doing better.

The other interesting thing is that award days overall are far less available on the return NRT-USA segment.