I made a higher, wider windscreen from polycarb, I'm 90% sure it was Lexan branded. I like bocutter's idea better, but I did it the lazy way. I heated it over kitchen hot plates, and bent it 90 degree's over a kitchen bench. Held it there for say 20 seconds, then it was set and sprung back to about 45 degrees. Did it a few times till the angles were the same as the original. If you use an off-cut for testing, that would tell you the temperature at which it bends, and the overheated temperature.
I had no problems drilling the holes, so I'm sure you wont have problems with brittleness.
I'm sure it's strong enough without extra support. When I finished it I couldn't wait to try it so temporarily only drilled four holes. I've been 200km/h with that screen. The other holes are still on the To-do list.
A temperature gun would have been a big help to avoid overheating, which results in white spots on the surface. I got a few white spots, but they can be scraped off, it's on the To-do list.
