You never mentioned how many years you have at Spirit, which also matters. You may never be never be able to get the same relative seniority in 12 years, if you've been there for years. If you have already been there for several years and wouldn't mind being a NBFO for the rest of your career, it certainly doesn't make sense to me why you would go anywhere else as the pay isn't going to be different enough to change your life and may actually move you backwards on long term QoL.

To answer your question, though, seniority, like pretty much everything company drives what you can do with your schedule. Bid min credit and a schedule that will get bought off as an FO for OE, just to replace it with premium pay, essentially making 300% on your time at work... seniority. Vacation you want... seniority. Days off you want... seniority. Trades you want to either drop, trade into a lowers schedule, etc... seniority. As Brickfire said, your ability to do all of that depends what fleet, month, whether it is a dry summer in Borneo, etc. Too many variables to predict how well you can execute everything, but it is all seniority driven.