Don't machine down that clutch actuator.
It won't increase the pressure as it plays no part in clutch pressure limiting once it is released. What it will do is limit the amount of travel available to open/release the clutch assembly, so the clutch won't activate fully, always dragging.
Check the springs and replace the plates and the springs if they need it. You can't mickey mouse a clutch for very long, they will just fry. Feed it the parts it needs.
