I've read the directions several times and have been on search. How do I get the clear plastic cover off of the gauge cluster? I want to try to calibrate it with the cluster in place because my hands are big. I've rigged my vacuum pump and my t connection under the hood and I can get 10 pounds of boost on both gauges. Can I take the clear plastic cover off without removing the cluster? If I can, I calibrate it with the help of my wife. Thanks.