I have a later dunstall fairing mounted that is bigger than the little bullet style, early race fairings.. Needless to say, I did my homework on them..
Here's a beautiful early model one that I liked and saved this picture when I was doing the research for my fairing project. This bike belonged to one of our Aussie brothers here, and as I recall, he got into an accident with this beauty and it was totalled. I'm not sure if he's still here and I forgot who's bike it was, but it's a beauty.
Being a larger size person, that fairing wouldn't cover my nutsack...so as beautiful as it is, I went with a bigger late model version... below. I wasn't going to mount clip on bars because I don't want to ride in that position, so I just went with my 30 wide BMW bars with a pair of 1-1/4" offset brackets... It kind of works ok. The fairing is a little higher for clearance for the bars so I cut the windshield down a bit to balance it out to get the amount of coverage I wanted.
You can see it's a totally different application than the early one.....
My original mounting bracket was a "unicorn" shaped single arm bolted to the steering head that ended in a "T" which bolted to the underside of the "dashboard" of the fairing. That didn't work for me because it blocked my view of the ammeter that I have mounted in the headlight and the headlight switch (70 model has an ammeter which I mounted in the headlight shell) I took the unicorn arm of the mounting bracket and cut it short and made it into a fork to go around the headlight shell so I could see the ammeter and the top of the headlight with the switch and lights. In my case the headlight just bolts to the fairing, and no longer to the forks. I eventually modified that so the headlight was also mounted to the headstock bracket, so I could unbolt the fairing completely and the headlight would still be connected to the fairing bracket instead of hanging by the wire harness when the fairing is removed
the stock under the tank mounted lower arm brackets are crap IMO... I made my own bracket that is rubber mounted to the down tubes and supports the lower arms of the fairing... It's rock solid. You can see the rubber lined "U" bolts on my down tubes in the picture and maybe see the arms (they are painted black so hard to see)
here's the modified forked bracket picture below. You weld a piece of flat steel on the bracket top and use double nuts and custom made nylon bushings to adjust the fairing height so it sits level and squarely where you want it. You can also buy fairing brackets too... (google is your friend)