High string tension doesn't really mean can produce powerful smash indeed The higher your string tension the more accurate you have to hit the shuttle at the sweet spot in order to produce the power you desire. nicotine I suggest you change to BG66 with 22lbs, play it for at least 2 weeks. If you feel it's nice just after you re-string, you can try higher tension next time. If after couple of weeks you feel better, you should re-string for lower tension next time. And then raise the string tension gradually. Because we need accuracy as well, badminton not all about smashing.