What are your preferences for grip on serve - the first finger spread somewhat such as common with a forehand grip (pistol grip) or fingers together (hammer grip)? Does one grip or the other better facilitate the whip through the ball at the apex of the serve motion at ball contact? My observations during the Open (as best as I can see on a TV screen) seems to show both grips used. Is one better than the other or is it just a matter of preference? BTW, I use the pistol grip but was thinking about trying the other.