You don't have to shoot to test defences. Look at the main screen in the Class Design window. On here, you'll see the %chance for missiles to hit targets at 3k/5k/10k speeds, if I remember correctly. For beam weapons, you'll see a chain of numbers that give you an accuracy at each 10k distance.
E.g. 90 80 70 60 would mean 90% accuracy at 10k, 80% at 20k, etc.
Tracking speed determines penalties to hit. If the missile moves faster than your FC/turret's max turning speed, you'll incur a penalty. The specifics I am unaware of.