Re: Topspin vs Flat?
I play flat when warming up, it's good for my initial feel of the ball. Then I try to mix it up, if my feel on a certain day is bad, I go to flatter strokes until my feel improves. Originally my backhand was very flat and my forehand very spin, but in recent years it has become the complete opposite, even though my flat forehand still isn't as improved as my backhand spin.
When playing crosscourt, I rarely play flat, except when I'm on the run and am forced to play in open stance. The major problem of mine lately has been that I can't figure out which strings (and what tension) would suit me for playing shots with more spin - many budget strings seem to wear out and lose their friction very fast.