Smooth seas make the voyage more pleasant.
A ship in port is safe, and that's just what ports are for.
If you are both experienced wargamers then adding advanced rules should not be a problem.
True. But IMO there's no need to do so. The basic game is very good, and you can always add more rules later, as you see fit.
As for reducing playing time I can only recommend that you play fast.
But there are short-game options in the rules. If you do keep up the pace, though, you should be able to finish the full game in three hours.