If you are not a United pilot, you can't ride the jumpseat or be in the cockpit internationally anyhow. Don't know if an offline JSer can even be given a seat in back internationally if listed for the JS, since a JSer is technically a crew member who has cockpit access. And access to the cockpit is the sticking point for international jumpseating, not a CA's decision on whether to give you a nice seat. Even if you could successfully list JS and get aboard without the agent bothering on a run through CASS, you'd be the absolute back of the line for a good seat. You'll need to shell out for a ZED ticket to improve your odds a bit.