This is easy and a no brainer.

TAKE THE EMB IN AUGUST!!!!!!!!!!!!!!!!!!!!!!!!!

Seriously, if you wait for the RJ you'll end up sitting reserve in ORD or 8 months until you can get SLC and then you'll sit reserve there for another 6+ months. I you take the EMB then you'll get Fresno where you'll only sit reserve 1 or 2 months.

Get out of Mesa before the ship crumbles and take the FIRST class you can get at SKW seeing seniority is everything. The EMB is a blast and if you want to stay in Socal then your QOL will be much better as an EMB FAT FO.