Haven't ever worked on little helo's - just Sea Kings, but generally a good couple of hours. Have never used rotortuner - more familiar with old strobe lamp and reflective flags in old days and more recently using RADS AT kit to do track and vibros. You have to remember that RADS tries to reduce vibration at expense of track. However when doing tail rotor dynamic balancing, it's very easy to get into a "loop" by blindly following the box - must always remember that it references to a master blade all the time.