The inset dimension on the cam adjuster is so small of an adjustment I always just make sure that the cam adjuster is slightly negative. If you want to get it exact you can use a caliper and measure the depth to spec. Basically it is, remove the plastic cam adjuster cap, loosen the locknut, turn the adjuster until spec is met, tighten the locknut back up, then replace the plastic cap. Make sure you only tighten the plastic cap barely beyond snug, you don't want to strip it. Mine is a 1993 so please double check for any differences.