I'm not at Skywest, so I don't know if it's accurate or not, but it seems like they publish junior seniority at each domicile:
https://www.skywest.com/skywest-airl...es/pilot-jobs/

According to this, LAX ERJ CA is a little over 3 years, and SAN ERJ CA is pushing 5 years.

If I lived in SAN and had no intention of moving, I'd still pick OO over QX. LAX/SAN as an FO pretty quickly, and a Socal ERJ CA upgrade in 3 years or less. It's a future prediction, but it's likely to be less with OO's future plans and uptick in industry retirements.

Best case at QX as a SAN commuter, you get PNW based with a 2+ year upgrade.