I can try to answer...
The shortest I've seen... is... No reserve at all. Yes... I've seen folks come right out of training and into a "Line" or regular schedule. The longest... I've seen folks go several years. It really just depends on the situation at the the time for that particular airline.
As far as your domicile goes... you do get to choose it... kinda.
You place a bid for it during your initial training. If your company has 5 domiciles, then you would list the five in your order of preference, and then submit that list to crew planning. They will then determine where they need the most pilots, and then select from your lists in order of seniority. So... it's entirely possible to get your first preference if it's a fairly junior base/domicile... or if they are short of folks at that base @ the time you finish training.
Does that make sense? Let me know if I can clarify it for you...
Bob