I can't speak of Paiste cymbals as my very first cymbal was/is a Zildjian and I have not strayed from them very much (a Wuhan china cymbal [which, by the way, was MORE difficult to pick out] and a small ran-can bell effect cymbal [AKA "the ash tray"] is about it).
Zildjians are very complex. Weight can tell a fair bit in a crash, but I've found it tells nothing in a ride.
Besides weight, the curve (or bow) has a distinct impact.
Bell size and shape
The stick you use on it (of particular importance with regards to sound files recorded by others and critical on a ride!)
Where exactly the weight is- is it even thickness bell to edge or is it thicker toward the bell and thin on the edge? In this case two identical weight cymbals can have radically different behaviors.
I have a 20" ping ride (I like a lot of 'stick') and I also have a 22" ping ride. I thought the 22 would be 'more' of what I get with the 20- more volume and some more wash (since the 20 is a tiny,tiny bit dry). WRONG. The 22 is a totally different animal- like if it did not have the ink on it, I would not peg it as a ping ride at all. Still a cool cymbal, but not at all what I was expecting.
What does all this mean? As inconvenient as it may be, either you will be buying and selling a lot of cymbals to find the right one, or you need to drive to the cymbal (and bring a 'key' cymbal with you- I use my 16" thin crash for this) and play it and your key one yourself. That is the only way.
Paiste's may be more consistent from cymbal to cymbal but I don't have the experience with them to say for sure.
EDIT=> I wanted to add that although Zildjians are more work to find the perfect ones, once you do, it is very hard to replicate that. Each one is very unique, so even replicating the entire set-up of so-and-so drummer you may not have any of the same sounds...
