I have used Hdoc method above and with the addition of slight silicone to the outside part of the belt not the grooved inside I have manged to get over 50 flights and belt still going 100% not showing any deterioration.

Before this method some lasted 5 to 8 flights but I was over tightening the belt. Trick is slightly less than by the book (as slack as you can but tfat your tail rotor does not slip when you move main rotor) and a little silicone oil on the outside once only.