Im installing the OHC but I got to wait for the paint to dry.

How far back do I need to place the brakcet from the windshield to start cutting?

 

Position the OHC where you want it, then trace around that, marking where the tow clips are, because thats where you need to pay attention to. Take the ohc down, and put the bracket where the clips go, and cut the outline of the bracket out of the liner.

 

A tip from someone who's done this...

Cut from the center out. Cut smaller then what you think is necessary first. Remember, you can always cut off more, but it's very had/neigh impossible to put the liner back and look uncut.