Here's a quick and easy
way to do these.. Its not perfect but it gets the curve real close.
First take your tape measure (Or what I use is a Cloth tape used in sewing) and
stretch it across the top of the windshield from corner to corner. The take a
ruler or another tape and measure from the bottom of the arc to the tape. This
is your Draw. Now in your Graphics program. "I use signlab so I'll be talking
their commands but I know other programs are similar"
Make a guideline and put your wording on that then make a second guide your
measured distance parallel to the first. Click on your Transform/Bounding
Box/Arc/Vertical and transform your graphic to the lower guide (2" in this case)
cut and install.
Hope this helps we do around 20 a week this way and never had a complaint yet.
Canon City Colorado