Hi there, I'm tired of my SP setup. Due a knee injure my technique is suffering a bit and using SPPP 17 + string ports is not helping. My groundstrokes are quite unstable and I believe that using a 16 poly + string holes might help! I'll try http://www.tennis-warehouse.com/descpageACUNIQUE-UBIGHIT.html (Big Hitter), but I'm not sure about the tension. I'm thinking about 55. What do you guys thing?