Just did the same thing to my Hitech HG5000 gyro. Got rid of the need for trim in the TX. Before , I had to use +10 trim to cancel drift in HH but now it is 0.
Great tip. The flashing light sequence is the same as you described. Once all the LED's all start flashing at once , the cal procedure is finished. Unplug battery. Plug in and then play.

Thanks

Don