Counterweight size – zero swing

Hello Folks Is there a typical ratio (or even rule of thumb) of between the weight of a machine and its counterweight, especially in respect to the "zero swing" machines. Does the "ratio" vary much between a small digger and a larger one (I'm particularly interested in the smaller sub 4 tonne machines)? Is there anywhere where one might find data on the counterweight size of specific machines? Many thanks Foster