Thanks for your help with this. You're both right, it's down to being *even more* flexible with the travel days than I thought I was being, accepting that there's no way to filter BE from the results, and accepting a $120 increase to whatever most of the listed prices were. By changing to e.g. Wednesday - Thursday 8 day trips, I'm able to get the prices down to something close enough to UA/EL to get the flights approved.
Whew, I was eyeing EL and worrying I was about to waste a year of travel for no usable gains.
Thanks again, it's really appreciated!