Here’s what I know from my non-scientific research when I was persuing Alaska. The current jr man in PDX is 1.5-2 yrs seniority. There are dozens of pilots who live in PDX who are still serving in other bases. There even more former VA guys who live in PDX who will like to get home based too. I ultimately concluded it’s going to be over two years for a current new hire to get FO PDX. Probably closer to three or more to hold a jr. line. It didn’t seem like a QOL highlight to me.
I’m not a AS employee. I do not have solid numbers. I only have antidotal evidence through calling my AS pilot friends to ask about this same question.
Hope this helps in your endeavors