I need to fly SFO-NYC leaving on Sunday night in about a month. I checked upgrade availability and found nothing on CO or UA nonstop flights to EWR/JFK (I'm willing to use miles to UG - not EUA).

I am a CO plat, and usually fly CO in such cases due to the slight chance of EUA. However, in this case, if I assume that my UG chances on CO are slim to none, does it make more sense to book the UA PS flight? I can also waitlist myself for a UA upgrade using UA miles (although I have no status with UA). My logic is that if I assume UG doesn't clear on both carriers, UA is a better choice as I will get to sit in UA Economy Plus. Does that make sense?

Thoughts?