See my earlier post. Even as SE, there's no reliable way to get upgraded without using eUps or paying for it. You can book a flight that looks full, but (a) the flight may not be full, (b) even if it's full, there may be misconnects or people who change plans, (c) other people may use their eUps, (d) other SEs may get op-uped before you, (e) if no status pax have requested an upgrade, they may put AC staff or random people up front. All of which would leave you in the back. And there's probably a few more I haven't thought of.

Bottom line, use eUps, or pay for it, if you want to sit in J, and look at any op-ups you do get as a bonus, but there's no way to guarantee them.