My first thought of purchasing a full windscreen came while traveling the interstate. I got clocked by a large beatle directly on the forehead just above the glasses and below the helmet line. I thought if it would have been a nut or bolt kicked up by a vehicle it would have been a disaster. Good point about fogging issues. Both valid.
I think I'm going to go with the NASCAR Style Tallboy +2. Nice clean look! Only drawback would be exhaust fumes in the cockpit. I've read of issues with some tall windscreens in combination with certain tops experiencing this problem. BKL Br4hm4 , kev or anyone else using the NASCAR Style Tallboy +2 along with the Bullet Speed V-Back Top (or similar) having exhaust fume issues?
Frank depends on the exhaust system you have. A lot of different factors that can cause fumes in the cockpit. Windshield, top, and where the exhaust is exiting the Slingshot (probably the most important).