The simple answer is that officially there are no international upgrades though many of us on this board have gotten OPUPs generally as a result of economy being oversold. In that event, they generally go by elite status so without status, your chances are zero unless you buy up to a more expensive fare class that is upgrade-able and then happen to have a SWU you could use (and there is availability). I'd plan to sit in the back!
Rather than start a new thread, search would have identified plenty of others on international upgrades that would have answered your question for you.
As for sleeping on board, Ambien works great but you'll need a prescription and I would recommend waiting to take it until the plane is in the air. Last you want is the flight to be cancelled after boarding and after you've drugged up and you're immobile for awhile trying to maneuver around as you de-plane.