Klock Werks now has their famous Flare Windshield available for the Harley Low Rider ST. They currently have the 6" Dark Smoke Flare option available, but are working on rolling out more colors and and height options as quickly as possible.
The Flare Windshield is all about air management with the patent windshield "hips" and "top flip" shape. Height isn't everything, you actually want to be looking over the windshield. You can check out this video from Klock Werks to help you determine the correct height for your personal setup.