Everyone always wants to know how long to hold a line and it's never an answer anyone can answer becasue things change all the time.

You're only notifiable during your notifiable period, but the reserve day is 0001 to 0200 the following day. LCR is notifiable 24 hrs and SCR is either 0300-1500(RE1) or 0900-2100(RE2). So they can call me as early as 0900 on RE2 for a 1100 show, unless they notified me in a previous notifiable period for an earlier show, but that never happens on the FO side. New FOs fall into the trap of answering their phones outside a notifiable period and then finding themselves notified - don't answer your phone outside your notifiable period is the hot tip, unless you want to fly of course.

In SLC you can get a composite line immediately, and you'll be able to get a full line in your 2nd bid if you accept all pairings. Seniority happens so quickly for FOs that you don't have to wait long for anything, so don't stress about when you will be able to hold a line or a particular base. The same cannot be said for captains however.