If I remember correctly I unbolted/loosened the stansions first, having someone hold the windshield in place until we could tilt it back tward the back of the car, It has been a while so my memory is a little fuzzy, but it seems like it cam right off without too much effort. Mine had a rubber seal between the bottom of the glass and the cowl. the glass slipped right out of the seal then I had to peel the seal away from the cowl. Used an X-acto knife to get all of the sealer off of the paint.
Like you I just bought a set of the larger headlights for my Roadster. Got mine from Robot here on CHR (thanks Mike ;) )... I am looking forward to getting those painted and mounted over the winter...
Dave Brisco