I found this achievment really hard! Took me about 3 to 5 hours to complete it. It was just so tedious doing it over and over again! I can't remember how I did it but that sense of satifaction when I got the achievment was brilliant! It is one of the best
achievments ever due to the satisfaction you get out of it.
Had this done on an older live profile. Before i went into another one of my moods against modern gaming. I usually use youtube as my source for helping with stuff. The video i used gave you a good detailed step by step guide. Took me 20 mins after that
to nail it.
You get this weird sort of floating sensation when you do learn how to do the mission though. Least i did.