Try testing on your back patio, starting with cold water (chilled in your refrigerator). Weigh the canister before and after to determine how much fuel is used. That way you know how much fuel is needed for your specific style of cooking. Do this several different times and calculate the average, adding enough for one or two additional meals for "fudge factor." If it's cool outside with a wind, so much the better--more realistic conditions!

You should be testing your meals before you go out, anyway. Nothing more horrible than getting out and discovering that the dinner you had planned as a special treat turns out to be inedible! (Been there, done that! )