Note on installing/removing sliders. Bending them in the middle to get them in and out invites disaster, and is not a option if the stiffeners are already installed. When installing, screw in the front, rear, and bottom channels. Set the windows (stiffeners installed) in the middle of the bottom channel, slid together, tops tipped into the cabin. Set the top channel on the windows, and tip the assembly into the frame, screw the top channel to the frame at each end, and your done. Slid the windows together, unscrew the top frame, and tip in to remove. The fuselage frame for the top channel was left open on the inside to allow installing them this way.
If you make your own stiffener channels, (.032 aluminum works good), you can make them wider (about a inch). This makes enough glueing surface that riveting them on is not nessesary. Anywhere you drill, pound rivets through glass creates stress points that can eventually crack. You can also leave one end of the U channel long, and bend it back at 90 degrees to make a simple and effective handle. If you install the rear window in the inside, you can put a handle/lip on each end, makes it easier to operate the rear window from the front seat.
On glass type, Lexan and Plexiglass are names used be many manufacurers. Typically, Lexans are softer, do not break, but scratch easier. Plexi's are harder, some break REALLY easy, and are more resisant to scratching. Do not ever use the cheap hardware store Plexi's, way to brittle. I too, have soaked Lexan in fuel for days, exposed it to fumes, ect., I could find nothing to make it cloud or distort, maybe some cheaper grades will. Use a high grade of Plexi, or Lexan, consult your local glass shop, tell them your application involves fuel, scratching, temp extreams, and lots of vibration and sun exposure, use what they recomend in the brands they carry. And bug spray eats everything plastic or acrilic, (read the back of the can) keep it away from windows of any type.
Also beware buying precut window sets from suppliers (I'll mention no names) that seem rediculously cheap, they are made of cheap material, and not worth putting in.