VPN, the first thing I did was check to make sure the mounting points on the mount closely matched the points on the fairing. Fortunately, only one point was off and only by about 1/16". You should be able to easily get the bolts to thread int the fairing through the mount before you start on the rst of the job.
Once the points line up, I took my 3/4" plywood base and made sure it was perfectly square between two edges that I could use as baselines.
I put a centerline on the board parallel to one of the reference edges. Then I put a line square to the centerline. Rip a 2x4 about 20" long to 2" wide. Mark a centerline on the top of the 2x4 and mark and drill 1/4" holes for the two wider mounting points on the centerline. Find the point exactly halfway between the two holes and mark it.
Place the 2x4 " the plywood base so it is on the line you made square to the centerline and the center mark on the 2x4 on the base board centerline. Drill through the holes in the 2x4 into the base board. Attach the 2x4 and the mount to the base with 1/4-20x4" bolts with fender washers on the mounting points.
With the mount attached to the base board, use the other two mounting points as drill guides to make 1/4" hloes to bolt them to the board. 1/4-20x1 1/2" bolts with fender washers bolt them down.
A piece of 2" schedule 40 PVC pipe is almost exactly the same size as the steering head. I used a piece about 20" long, but 12-14" will work. A 2 1/8" hole saw cut a plug for the end of the pipe. A couple wraps of electrical tape made it a snug fit in the pipe. the hole saw's pilot made a perfect hole for a pencil to use as a pointer to indicate center. With the pipe cut perfectly square and the plug flush with the end attach the pipe to the mount with a hose clamp.
Use squares to project the pencil point down to the board and make a mark on the board to show where the center is. Reverse the pipe and make a mark at the other end. The marks tell you which way you need to move the pipe the get it centered over the centerline on the board.
Once the pencil point in the pipe is over the centerline on the board the center of the fairing will be in line with the centerline of the bike. In my mount the mount was tilted and pushed off to one side with my starting marks on opposite sides of the centerline almost 3/4" on one side and about 1/4" on the other. A bit of enthusiastic wailing on the sides of the steering head mount brought the centers on to the centerline and mount was ready to put back on the bike.
The only critical part is taking the time to make sure the mounting points are perfectly square to the centerline and equally spaced around it. I spent about 2 1/2 hours on the whole job, making the jig and straightening the mount. Once the jig was done the actual work on the mount took only about a half hour.
If there is interest, I can start aa thread for the lieberry with some photos and dimensions.
