The camshaft position sensor should come with a paper spacer at the point of contact between the sensor and the wheel. When installing the sensor, the paper spacer should touch the wheel, giving you the right amount of spacing between the two.
What I did when I installed the sensor is I put the sensor in and apply very light pressure from the back with one hand to make sure the paper is touching and put the nut on with the other hand until the sensor is immobile. Then tighten it. Hopefully that's correct.
what happens if the sensor touches?