There is no such thing as the vest singles racket, you have to give more info about your game, to see which suits the best.
You probably want a racket that induces a fair amount of power but still gives you control. All three of those rackets listed would be perfectly fine for singles. VT80 is particularly nice if you're aggressive.
If you think the Z Slash is a little too stiff for you (and you haven't misinterpreted the racket) then you can pretty much discount a VT80 or anything labelled "stiff" in the YY catalogue. In truth the Z Slash is not a Stiff racket, despite it being named that... You should probably consider a VT60 if you think the Z Slash is too stiff.
What about your play style? Are you an aggressive smasher or a "placement guy" or a defensive runner? What racquet have you been using which you felt the most comfortable with? The Arc-Z is hardly that stiff when compared to most of the other "stiff" racquets available today. If that is bothering you then you could try the medium flex ones such as Arcsaber 7, Voltric 70 or even the Arcsaber 9 FL
I already try those 3 racket (borrow from my nephew). AT900T is not for single. This is the best drive & defend racket ever Arc10 & VT80 both feel similar, very solid, stiff rackets. The difference is VT80 is feel more headheavy. Arc10 is more allround.
On the contrary the AT900T is actually pretty good for singles. It is suitable for the defensive and control shots-based singles player who patiently waits throughout rally then the winning shot due to the aerodynamic frame shape and pretty stiff shaft which make it responsive. I agree that the VT80 feels like a more offensive-based Arc10 with almost the same properties in the other departments
maybe you might want to consider the Victor Bravesword series, if you like the speed the ArcZ gives you, something like a Bravesword 11 or Bravesword 9 might be good choice, as these arent incredibly stiff rackets, and are really fast.
I have a Arcsaber Z-Slash, you know if you get the frame of the racket is smaller compared to other rackets, but the racket is really good for speed and power. I would say it is better to get the Arcsaber 10 for singles as these rackets are similar except for a few differences
