The present inventive disclosures are generally directed to various improved versions of locking compensated nuts for fretted stringed musical instruments. Many embodiments are especially directed to improved locking compensated nuts that can be more-easily retrofitted into existing guitars and other stringed musical instruments without requiring any major reconfigurations or modifications of the base instruments, and some variations are directed to a detachably coupled tuner-mount device that will facilitate enhanced tuning capabilities because of improved vibrational communication between the instrument strings and the tuner. In addition, some improved locking compensated nuts described herein feature interchangeable compensated inserts to allow for easy adaption to alternate string sets.