A slider, flexure finger, head suspension assembly, head gimbal assembly, main flex circuit, actuator assembly, spindle motor, embedded circuit, and hard disk drive using and/or supporting method of estimating flying height of read-write head near rotating disk surface. Method senses leakage current between slider and spindle motor to create potential difference measurement, and converts potential difference measurement to create estimate of flying height. Method controlling flying height using method for estimating by adjusting vertical actuation signal to micro-actuator assembly. The invention includes methods of manufacturing and their products.