You're better off buying a good sized roll
I can garuantee you'll fuck it up!
The way they did mine was take the passenger rears out, shrink fitting it to the outside of the window first (to get the curve) then swap sides and smoothing all air bubbles out. Then cut the excess off round the edge, leave to dry and the jobs a good un.
Having a full roll gives you some extra to play with so you dont have to worry if its squint etc.
The rear screen you'll need to remove all the trim and probably talcum powder it on as its a complete bastard...and if you fuck it up you'll lose the use of the rear screen demister