Use a low head socked head bolt and fit the brackets to the tank first on the inside with the head on the inside. Then lower the tank and bolt it on to the original hole with the original bolt. To do this you have to loosen the rear bolts in order to lift the tank enough to fit the brackets.
This is the study, and later I have painted the brackets and put dome nuts on to make it look better.
It gives quite a change in the appearance of the bike. Not easy to see, but if you know the bike you will see something's changed. I like the look with the elevated tank. When i put on the dragbar it will look great.
This is the before picture..Look at the gap between the seat and the tank, also the angle on the tank.