The stock StreetGlide windshield is NOT made for highway cruising. It's more of an around town type of windshield. It basically SUCKS! Much too short for highway speeds.
The ElectraGlide and Ultra windshield heights are more suited for highway speeds.
Especially at your height, you'll need a substantially taller windshield than a stock StreetGlide shield.
As you are going down the road at highway speeds, put one hand out in front of your face/helmet about 6 inches out and feel where the blast of air is coming off your windshield (I'm betting about nose/mouth level).
At that speed, the blast of air location on your face will determine how much taller your windshield will need to be to get the blast of air over your head.
If you go faster, the windshield will need to be taller, as the blast of upward moving air is also being forced backward by the forward momentum of the bike.
I'm 5'10" -ish and have had good luck with 8-9 inch windshields in the past. You may need a couple more inches taller since you are a couple inches taller than me.
Depending on your preference, ..... typically....., you want to look over your windshield, not through it.
I use an adjustable windshield.... 8" normal position that I can look over and in bad weather (rain/cold/etc) it converts to 14" so that I'm completely behind the shield if needed. Takes a few seconds to adjust/convert heights.
See video of the adjusting process:
https://youtu.be/oYIr_qFB6eg