Yeah, for sure I would not recommend 1/8 for the windshield. 3/16 is it which is more or less a micro under the standard thickness of tempered factory windshield glass. strong and light.
1/8 is too thin and will bow inwards at speed.
The front tires sound like a sound way to get rid of that nasty rotating weight. Kind of like comparing Good cholesterol to bad cholesterol.
If you go the route of Lexan with a flat sheet, you'll have to cut very careful making sure that you do not cut over the actual size especially when asking the Lexan to bend to and fit into the radius of the windshield brim. You'll have to use more or less set screws through out the whole brim to help keep the flat sheet in place and shape. Good luck.