Be careful how tight you pull when you are trying to get it on the hooks at the back window! I did mine three months ago , and pulled the first one too tight ! Oops! Had to spend another $100.oo and try again! Probably should have bought a sowing my-sheen ! ( ha-ha! ) I used the middle holes on mine.
Good luck! And if you have someone who can help , use them ! I did mine by myself, It would have been nice to have an extra set of hands , if for no other reason than to hold the darn thing up so you can see what the heck you are doing !