Windshield

[Meanguy]

My wife wants a windshield for her bike she said her neck is tired after she rides. I searched the old post, but what kind of windshield would you recomend? She is about 5'6". I was told that I did not need to buy a very big on because wind blast from a tractor trailer might blow the bike off the road, I have heard that wind can push smaller bikes across from one side of the lane to the other. I would to get get her one that is big enough to do the job but not too big. Thanks for your help, Charles