This Friday, I am flying SMF-SFO-EWR; this Sunday, EWR-LAX-SMF. I have applied RPUs to both, and am waitlisted. SFO-EWR has four open 1st (do I call them F?) seats left. EWR-LAX has seven open 1st seats left.

1.) What are my odds of making these upgrades using RPUs? Is there any way to improve said odds, short of buying the upgrade?

2.) LAX-SMF is two class. Using the RPU bumped me to 1st for that segment. Of course, it would be a waste to use an RPU for a 1.5 hour flight if I don't also get the EWR-LAX upgrade. The United rep I talked to on the phone said that if I didn't get upgraded on EWR-LAX, I would keep the upgrade on LAX-SMF but would not be charged the RPU. Should I believe her? And if yes, is this a tricky/risky way to use RPUs for segment upgrades?

3.) The most subjective question - is this the best use of RPUs? I can't imagine many longer flights that I could apply them to.

Thanks in advance!
Yours from economy, where people play Candy Crush at maximum volume, sans headphones, all flight long,
Rachmaninoff