Thanks for the further advice.
Yes, it would be simpler if I could fly direct to TLV. But direct AC service isn't available daily and on my planned travel date I can't find any better connections from the West Coast.
Best solution, for now, seems to be to either sit in the back for the one segment or to snare a UA systemwide upgrade (I'm hoping however that it will be accepted on an AC-issued codeshare ticket.)