1). S2B is pretty useless. If the seats are tight, all the S3s will start playing the S2 game, forcing your wife to do the same. I guess slightly better seating / better chance at upgrade (if that's even a player) make it worth using--since it's free--but don't count on it getting your spouse on if there are a bunch of non-revs vying for the last seat.

3). Be sure to generously tip the driver for any "extra" pax you bring along.