Do you mean in tourneys or what?
In tournament they divide you by weight, And the weight classes all depend on how many people there are.
Some shuai chiao tourneys down here everybody just fights everybody....
The way to get best is to fight all kinds of people of all different body weights though, and thats what I try to do.
Strength always plays a part in shuai chiao... You use your opponents energy against him, but you compress him like a spring first, load him... But you have to have the strength to do that, otherwise the throw wont work, and the throw wont be ballistic. Shuai chiao is like compressing the spring, and when the spring releases you help it a little.
Hope that helps.