Hey Andy, I have a 1/4 fairing on my Harley and I'm putting one on my CB750 as well. I actually used a set of Turn signal relocation brackets and mounted mine that way. If you want me to send you some photos, just let me know and PM me your e-mail. It's very sturdy at highway speeds and does a good job at getting some of the air up over your chest/shoulders.
You can also use the after market "headlight mounting " brackets apparently, but for me the turn signal relocation brackets worked much better. A couple nylon locking nuts and two holes drilled in the fairing....works perfect and super easy to take off and put back on..... Let me know if you have any more questions. Good luck on the project.