Its possible to know the no of flips you can get from a tank...an approximate calculation anyway...
Lets say you have a 12oz paintball tank and a 50mm x 75mm bore x stroke ram. So you start off with a supply of 12oz liquid Co2 at about 20deg C, and a ram volume of 0.15lt

Density of LCo2 at 20'c=27oz/lt
Density of Co2 gas at 20'c at 8 bar=0.535oz/lt
Ram can hold 0.08oz of co2 at 8 bar.
mass co2 tank/mass co2 ram (at 8 bar) = no of flips
12oz/0.08oz=150flips approx.