1)- If you're going for plastic, plexiglas is easy for the home modifier. Add a piece of contoured wood to the window as a mock-up to fill in the missing front piece on stock glass. Cut a piece of plexi a little bigger than what you need and put the stock glass & wood filler in an oven with the plexi on top. At 150 degrees F, the plexi will sag around the stock glass in about 10 minutes. With oven mitts, take the stock glass out with the plexi on top and let it cool- another 5 minutes. Then trim. 150F won't hurt stock glass and it reproduces the stock compound curve perfectly.
2)- use UV-stabilized plexi or your new plastic window will sun-craze in a month or so of driving during daylight hours.
3)- tinting plexi can be done with green 'RIT' dye just like they do sun glasses. Dissolve the powder in hot water and lower the upper edge of the plexi in a tray full for about 1 minute then rinse to produce a tint band. Amount of tint can be increased by repeated dunks & rinses.
4)- polycarbonate is far stronger than plexi but needs around 300F to form it.. Lower heat causes air/moisture bubbles to form which ruins it as a window. Some high priced polycarbonate is silicon-coated (used for fighter plane canopies) but eventually it scratches, too. ALL plastic is softer than glass.