Not sure what racquest u are using but if u use Yonex - there is a recommended tension - for example Mp33 - max tension is 22. I have an Armotec 700 which can go up to 25lb. I visit a badminton shop in Singapore which does stringing for some ex-chinese and indonesian players. the guy who does the stringing advise me to try out the tension. the best way is to see if u can hit baseline to baseline. depending on ur strength /technique. if u hit it to far past the baseline - u should up the tension. if u are a beginner -better to use a lower tension racquest to get some bounce.
As for smashing like Lin Dan - even he use a 20lb tension string - he will produce great smashes.