Three options that I can think of off the top of my head:
1. Rifle makes windshields that are of various heights for the F. You have to use your original mounting hardware.
2. Budman made me a pair of longer, custom "one-off" extenders that pushed my shield forward (i.e. more vertical), which solved about 90% of my buffeting issues. He may not be able to help, but it's an idea.
3. Cut the shield down where you have chest protection, but clear air for the helmet. If you have the skills, this may be the best idea.
USAF: 1989-1997. Desert Shield (Saudi Arabia), Desert Storm (Kuwait, Iraq), Provide Comfort (Kurdistan), Restore Hope (Somalia), Uphold Democracy (Hati), Joint Endeavor (Bosnia), Support Hope (Rwanda). USAFR: 1997-2014. Iraqi Freedom (Iraq), Enduring Freedom (Afghanistan). Retired, Oct. 2014.