Although IAH is a completely different part of the country, it shares the hub aspect that EWR has, so I'll let you know about my experience.
I've had 100% success getting upgrades on the first flights of the day (IAH: 9:30am, OAK: 6:30am) between IAH-OAK as a Silver. I've even seen an empty seat in F once or twice. You've got the SFO competition in your favor, so that's a good thing.
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daniel baker --
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