As a mostly flat hitter, I am not sure what racquet will perform best for me. It seems that there are a multitude of modern racquets designed for spin. But, while I do hit with some spin, my strokes in modern terms are considered flat. Hitting with spin is hard on my wrist and elbow so I am not interested in changing my game style. For pain free tennis, I need a racquet that has some flex and is good for hitting consistent flat strokes. I'm only a 3.5 level player. My 1-handed backhand is my best shot; I like to drive the ball with a balance of power and control - I'm not a dinker! Should I use a racquet with 18 main strings? I use Eastern forehand and backhand grips. Thanks for your help!