Originally Posted by Freeflyfreak

You get very little info prior.
Day 2 IIRC in the morning they give you a ballpark idea of what is available.

Words to the effect of "X number of EQUIP/BASE, the rest are mix of EQUIP/BASE and EQUIP/BASE"
But you don't know exact numbers or the finish dates at this point, and that can make a big difference to your decision, it did mine.

In the afternoon of the same day they bring in an Excel spreadsheet.
On the top of the spreadsheet is the class arranged by age oldest first.
On the bottom is the equipment arranged by projected finish time, earliest first.
That bottom order is going to be the final seniority order of the class once decisions are made and names get assigned slots. (the seniority that most matters anyway, there are actually 4 seniority dates but I don't want to make it too complicated here)

You get a few minutes to look at it while they explain the process, they were very good about explaining the potential drawbacks of giving up seniority, and you get to ask questions (such as the status of a fleet/base), maybe 5-10 mins I would guess, but it may have been longer. (Time warped for me when I saw the list and the choice I was faced with).

Then they copy the oldest name, and say "OK what do you want" and paste him in his choice.
They go down the name list like that until all the spots are taken.
Didn't take long at all.

Hope that helps.