Just bought and played the Head YOUTEK Graphene Speed Pro for the very first time. Strung with Dunlop Black Widow full bed at 55lbs. The feeling seems bit boardy and hard to hit top spin. I decide to change the string back to my favorite, Volkl Cylcone 17. May I know what tension recommend for full bed of Volkl Cylcone 17 on Head YOUTEK Graphene Speed Pro? Thanks!