Short call is 2 hrs. I was only on reserve for one month, but in that month I usually got more than 2 hrs heads up. Min days off per month = 12. In between reserve day blocks min off is 3 days, however, NOT for the month-to-month transition. Theoretically you could get a 5 day stretch of reserve, 1 day off, then another 5 days from May 27-June 6. That's just an example.
Although the system is changing (I think), once you are awarded a reserve line in PBS, all it says is "RSV." Then the reserve bidding opens up and those are hard lines that are published, and you pick the order of the ones you want (like regular line bidding). In this case, you could bid to ensure you don't get a month-to-month transition conflict.
As for letting go early, if you don't have a flight assignment, you could be released. Again, I was only on reserve one month but I got released every time by 12noon-1pm which let me take the 1pm flight home to an east coast city. These days, I hear we are short on pilots and with attrition so they might not be as willing to release you.
