Definitely take a window & aisle and hope for an open middle.

As far as upgrading.. there was a comment in the other thread that UA is waiving change fees if you want to upgrade your ticket to an H or M fare..you just pay the fare difference which may work out to be around the same amount you would have paid with a copay (or maybe not...but worth checking). Then you can spend 30k miles each way to upgrade. But of course, if your upgrade doesn't clear you don't get any money back.