Welcome to the boat mate.
Sounds like you've got a pretty good set up going for you so I would suggest that you play the save several times and try using several different approaches and get some shooting practice. Consider it training missions.
You gotta learn sometime and this looks like a good time to do it. Once you get the hang of it 1600 yards is close range, 3000+ is long range.
Enjoyed your post so don't be shy. I like to hear how new people are progressing.
Magic