One more important point about David Ferrer...
He plays with a wrist band on his right wrist. This effectively adds to the weight of the hand, necessitating a much lower MgR/I value than without one. If you think that this sounds ridiculous, go try hitting your normal forehand while wearing a wrist band -- it noticeably alters your stroke.
BLX Blade 98. 13.74oz., 12.55", 370.5 SW.
Pre-Stretched Ashaway Kevlar 18g/Zyex Monogut Red 16g, 55 lbs