Flat serves, rackethead up and slightly closed face, but flat hitting arc at impact.
Topspin serves, rackethead maybe 45 degrees up, hitting arc barely upwards, closed face.
Kick serves, rackethead closer to level, but still up some, maybe 30 degrees, face closed but hitting arc more upwards than for topspin serves.
Slice serves, rackethead up almost like flats, hitting arc straight horizontal, racketface facing off hand side.
Groundies kinda depends on height of ball, eh?
And slice has racketface usually open, while tops are closed faced a little.....
In other words, depends on incoming ball, what you want to do, and how your style affects it.
