Any calibration LUT should be associated with the display, not the grading system.
Ideally, within the display, or an external LUT box.
Some grading systems allow the a calibration LUT to be used at the very end of the image chain, so as close to the display as possible.
With FCPX we have no idea what options are offered - you need to ask on an FCPX forum really.
Mob Boss at Light Illusion