GWX improved the AI so that a ships spot you at varying ranges, some ships have inexperienced crews and some have experienced crews, and then there are the very experienced crews. Generally in the earlier years you'll mostly meet the former, but as the years go by...
Weather/sea state does play a factor but again it depends on the crew, and is again quite random.
I can't help with your last two questions, in fact I don't even think I've helped with the first two
