What are you going to hunt with the shot bbls?  Ducks out of the flats?  Or Ptmarigan on the hillside?  I've shot a LOT of birds in Caribou Hills, but it's hard hunting there without a snowmobile.  Anyway, i'd get the longer bbls for the flats, and a bit shorter for the hills...
  I always liked my combo bbls, as i could hunt caribou or any other big game, and still have the shot bbl for ducks or whatever else was around.
  For me, it's double triggers all the way!  I love the instant choise of bbls.
  BTW, i found some great bird hunting in the interior too.
  DM