So I can't get both. If I Choose to get the first available coach seat on the early flight because I Really want the earlier flight, I can ONLY get upgraded if I am repeatedly pushy and there happens to be a First seat available and I don't board early and I tough it out waiting at the gate, and hope the agent doesn't get irritated with me, and wait to be the last passenger to board, and then not have any overhead space in economy if I don't get upgraded? Or PAY for a confirmed standby.
Don't know about the "repeatedly pushy" part. That may actually hurt your chances. You can get upgraded only if you are confirmed into coach on the flight AND all others previously confirmed and waiting for upgrades are upgraded AND there are still F seats open. It can happen and has happened to me more than once, but I understand going in that by standing by for a different flight I'm probably not going to get the upgrade.