I have been playing for 5 years now wth head light rackets. Last week i purchased a yonex armortec 900 power to play doubles with. I bought it becuase I wanted to smash harder in doubles and I personally think it is a great all round racket. When using it I have found you have to give it a real fast swing just to get anything out of it, also you have to use alot more wrist compared to a head light. I have always used nanogy strings on my rackets but the string on the 900 is bg65 ti from factory at 24lb. What should I do?