Delta
-12/13 depending on number of days in bid month
-12 hr call-out but can be placed on "short call" (with 12 hours notice) up to 6 days a month (in my category it seems to happen about 3 days a month on average).
-All long unless placed on short by scheduling at least 12 hours notice (usually about 24 hours notice).
-You can trade reserve days as long as mandatory groupings remain intact (example must be on at least 4 day blocks for international categories). You can trade days as long as day leaving is not below required reserves, and if it is, you can still trade if adding an even lower reserve coverage day.
-Impossible to say as it depends on category and with PBS sometimes there are only a few on reserve. Also, in my category, since the reserve guarantee is only 2 hrs less than average line value, many of the reserve lines often go senior to flying lines if there is anticipated extra pilots.
-I have newhire mentors who have only done one month of reserve in NYC and have a line in ATL within a few months. Lots of hiring right now.
-Lastly you can request trips out of open time but reserve flying is "metered" by a bucket "point" system which tries to keep reserve usage and "short call assignments" more even across the reserves available.