To avoid colliding with your tank, pull the steering to full lock, then rotate the clip on away from the tank enough to hold comfortably in your hand position. Then switch sides and repeat. Then, you have to decide if the riding position of the clip on location/orientation is comfortable for you. May be too much reach.
If you can't get them comfy, your options are: dent the tank (drag...) or different clip on rises with offset and angles.
My personal opinion:
I don't like the idea of shimming a clip-on. The tension on that piece needs to be STRONG to insure safety and stability. The last thing you'd want is for that to slip loose while steering under power in a corner or slow, long, leaned-over situation. Could be disastrous. There are many other clip-on vendors that make appropriate sized clamps and offer angled risers.
:End opinion.
Your may also require different cables due to change in length/height of controls...