With a linear throttle curve in normal mode, move the throttle to mid stick, and disengage throttle hold. Let the motor spool fully spool up at mid throttle for 15-20 seconds, and then bring the throttle back to zero and let it spool all the way down. Unplug the ESC and then set your desired throttle curves for your target head speeds. Since there is no way to set actual head speeds in the ESC like you can with castle, you`ll need to use a tach to get the head speeds you want. Hope this helps.