I did find and now run a Slipstreamer no vent #S-T167-T new on fleabay for a GL1800 that is 7" taller than a stock GL1800 shield, I look over it and LOVE it and at less than $125 shipped I love it even more. I have been well into the triple digits with it and no issues...oh did I say I LOVE it? It is a light tint and very optically clear when looking through it, it also has the GL1800 adjustment slots so it can be raised or lowered as desired in just a few min(I have that front cowl removal down to under 5 min).
I run mine all the way down.