I've done a couple... the easiest way is to get two sets of Headlight clamps, a normal headlight, some aftermarket indicators, a bit of metal strapping and some black paint.
Put the headlight on with one set of headlight clamps on the forks. Also mount the indicators to those clamps. Mount the 2nd set above those clamps just under the top yoke. Get the metal strapping and put two 90 degree bends at each end to that it fits between the clamps. Drill a hole in each end and bolt to the clamps where the headlight would normally mount. Then put the dash on the long section of horizontal strapping and mark were at least two of the dash board mounting bolts line up with it. Drill the strapping and mount the dash to it making sure you reuse the rubber mountings.
You can then angle the dash by loosening the two outside bolts to get it how you want it. The back of the dashboard is white so will stick out like a catholic priest at a playground so paint the fucker black. If you make sure the rubber plug protector is in place it'll keep the weather out... I never had any problems and I rode it in all weathers.