"how many minutes sunset is delayed for every degree west you go "
Err, isn't it simply derived from minutes in a day divided by 360
ie; 11540/360
=4
ie sunset is delayed 4 mins/degree west.
Latitude is irrelevant to the affect of purely westerly travel. OK you might not get a sunset in some places, but the sun will still appear to travel at 1 degree every 4 mins.
Or have a made some stupid gaff and should I delete this post to avoid deep personal shame?