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.
The penalty for shooting at a target that is faster than the fire control speed is the ration between the tracking speed and the actual speed of the target. If your target is twice as fast as your tracking speed then the base chance to hit will be divided by 2. Three times faster, and the chance to hit is 1/3 of normal. This is linear thankfully so it is not hard to extrapolate from the info on the ship screen.
Brian