Any big hitters using the Volkl PB 7 oversize frame? My 16 year old son is a tournament player and has been using the frame for over a year. I was interested in it, and gave it about a month of regular indoor use this winter, but never could work out my serve. Did like it for everything else though, but went back to my less powerful Becker London. My son is really starting to hit the ball very hard, and I am concerned that this frame has too much power for him to control. But he does not want to change frames, so I guess I need to try and tone it down through string and tension. I'm currently stringing his frames with Volkl V-Pro poly in the mains, and Head Rip Control in the crosses. Normal tension is 59 mains, 64 crosses. I'm thinking about going to all poly at maybe 63 or so. Anyone playing with the frame strung anything like that? I really feel like he needs to make a racket change, but he does not seem too hip on the idea. Suggestions?