for your front windshiel of the citadine, you have to built by fin woods a model, and after on it you have to place the new plexi.
if you have to curve only the corners you can warm it at this place with a " décapeur thermique". if you do mistake who can warm it again.
the plexi can be work on 100 °c to 140°c but not more because after it could be to hot and damage the plexi.
you have to wait 70 or 80°c to stop press the plexi to work your shape.
hope to help
pierrick