According to spherachutes' weight chart, a 30 inch parachute should work in one of my rockets. However, when I build the rocket in RockSim, the parachute (after I've converted the parachute "size" into a diameter measurement and entered the spherachute Cd), is too small. Which source should I believe? Erring on the side of caution is a good thing, but if I put a big motor in this rocket, I don't want it to drift too far (It's single deployment only). Perhaps I should put a big 'chute in the rocket and only launch it on calm days?