The previous posts have good advice. Patterning is key. It really doesn't matter anymore about the patterning percentages always quoted with lead loads when your talking about the non-tox as the new stuff is all different and patterns different. The choke is just a constriction that is supposed to print a cretin percentage of pellets in a 30" circle at a given range with lead. Even with lead it is dependent on shot hardness and other variables. There is all kinds of technical information about the chokes and percentages but what you are really looking for is a good pattern that is well distributed over a 30" circle or better if possible. The density of the pattern increases with constriction to a point. Pattern different chokes with different loads and see what the gun is doing. You want patterns that will put 5-6 hits on the size target you are hunting at the range you are shooting. A few more is fine but you don't want to over due it if your eating it. Know the distance each choke shoots a nice pattern with each choke and take the chokes hunting. Change as the shooting range changes selecting the one that best suits the average range your shots are at.