Can't comment on gundog coats. The best all-round coats I've seen are "slape" collies, the rain/snow runs off, they don't gather crap/debris, aren't too heavy
Probably suffer in real cold though, everything has a thick double coat, my dad apparently had a Samoyed cross as a kid that you couldn't see sleeping in the snow covered over. Seen huskies on the TV doing the same, no kennel just staked out on a windy hill end