Dropped the National Cycle Deflector and busted it all to pieces so have installed a new SlipStream Cobra Windshield complete with hardware. IMO, it is perfect in size and style. The "tee-screws" do loosen, but I have them preloaded with small bungy cords so they don't move at all. Had no issues with the SlipStream plastic mounts that go through the windshield.
Let's see some pics!!! I went with the viper but considered the cobra for a while.