Someone called?

Sorry - I've been up for 20 hours now - long story. But yes, all of SkyWest's CRJ700s that operate for United Express are configured in the eXplus layout (including your SFO-SNA-SFO segments), consisting of:
United First: 6 seats (rows 1-2, A-CD seating)
United Economy Plus: 28 seats (rows 3-9, AB-CD seating)
United Economy: 32 seats (rows 10-17, AB-CD seating)

Exit row: 12. Avoid 12A/12D if you value your posterior

Happy Travels!