I've owned a LL for a couple of seasons now. I agree with your assessment. The biggest thing it does is to smooth out the turbulence of the air coming off the top of any windshield.
I use mine mostly it on my Ahamay Touring accessory shield (+2") with the Rifle Tuning block installed (which makes the Ahamay only as high as the stock shield), but also have the velcro buttons mounted on my wider Rifle Sport model.
Another nice thing about the LL is if it does get really hot and you need more air, it can be removed out along the side of the road. Finding a place to stash it is the only issue.
And great idea on the nut n' bolt. Belt and suspenders works for me. I'll have to try that.