i am a 3.5 doubles player that plays in 60+ leagues and i have a lot of trouble with trampoline effect when blocking hard shots,vollys and lobs. it happens after the strings lose tention in about two or three weeks of use.i have been using psgd 16 and like it real well for first weeks.have tried a lot of strings but most are to powerful.does anyone know of a stiff low powered string that will hold tension and not trampoline so soon. thanks